Actuator structural body

ABSTRACT

An actuator structural body is constructed of standardized columnar bodies connected for moving a workpiece. The Actuator structural body includes actuators shaped as columnar bodies and having T-shaped grooves defined in outer side surfaces thereof, columnar member shaped as columnar bodies and having T-shaped grooves defined in outer side surfaces thereof and through holes defined therein, and joint members for joining the columnar members and the actuators bodies 204, 206, 208, 210 by engaging in the T-shaped grooves or fitting in the through holes in the columnar bodies. The columnar members 202 and the actuators bodies may be assembled or reassembled into a desired shape by the joint members.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to an actuator structural body comprisinga combination of actuators actuatable under a fluid pressure or bymotors in a line for conveying a workpiece or the like, the actuators orsupport members which support the actuators being connectable ordetachable by joint members.

2. Discussion of the Background

Actuators have heretofore been employed as a device for attractingworkpieces with a suction pad or a device for gripping and conveyingworkpieces with a mechanical hand or a chuck. Such an actuator ismounted on support members at a given position thereon, and moves amovable body comprising a table with a drive source such as aservomotor, a stepping motor, or the like through a drive mechanism suchas a ball screw, a timing belt, or the like. As the movable body moves,an attracting and gripping means coupled to the movable body also movesto convey a workpiece attracted by the attracting and gripping means toa desired position.

According to the above conventional art, if an actuator is mounted onsupport members or the like which are assembled, then the supportmembers have to be disassembled and reconstructed again when theactuator is adjusted positionally or replaced. Such a procedure istedious and time-consuming.

SUMMARY OF THE INVENTION

An actuator structural body according to the present invention has anactuator and a columnar member which are shaped as columnar bodies andhave T-shaped grooves defined in outer side surfaces thereof, and ajoint means for joining the columnar bodies by fitting in the T-shapedgrooves. When the actuator is to be positionally adjusted after theactuator and the columnar member are assembled, it is only necessary toremove the joint means, move the actuator, and join the actuator and thecolumnar member to each other with the joint means. The actuatorcomprises a first induction motor and a second induction motor, its sizeis smaller than if it were composed of a single motor, and no motorprojects from an outer side surface of the columnar member, which canthus be reduced in size.

The joint means may comprise an engaging member having a shank insertedin a through hole defined in the columnar member and a head engaging inthe T-shaped groove. A tightening member is threaded, from outside, intoa threaded hole communicating with the through hole, and pressed into arecess in the shank to fix the columnar member to the columnar body. Thecondition in which the columnar member is fixed to the columnar body caneasily be varied by turning the tightening member from outside.Alternatively, the tightening member and the shank of the engagingmember may have respective bevel gears, and the tightening member may beturned to press the head of the engaging member into the T-shapedgroove. The through hole of the columnar member may be used to housewires or as a fluid passage for simplifying a wire or fluid passagearrangement leading to the actuator. A cylinder may be disposed in theactuator, and a pulley body may house a moving pulley mounted on thedistal end of a piston rod of the cylinder. A fixed pulley may bedisposed on an actuator body at a stroke end of the cylinder, and a wiremay be trained around the moving pulley and the fixed pulley so as toextend from the actuator body at the stroke end of the cylinder toward amobile member. When the cylinder is actuated to displace the piston rod,the movable body is displaced an interval which is twice the interval bywhich the piston rod is displaced. As a result, the stroke of the pistonrod may be reduced, and hence the actuator may be reduced in size.

Furthermore, a fixed pulley may also be disposed on the actuator bodyremotely from the stroke end of cylinder, and an adjusting pulley may bedisposed in the pulley box. Another wire may be trained around theadjusting pulley and the fixed pulley so as to extend from the actuatorbody remotely from the stroke end of cylinder to the movable member.When the movable member is displaced in either direction, the pulleybody is displaced, and hence the wire is prevented from being slackenedoff the pulleys. The movable member may be integrally formed with amovable member associated with another actuator, so that the actuatormay be used as a balancer for the other actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrative of an actuator structural bodyaccording to the present invention;

FIG. 2 is a perspective view of a first embodiment of an actuator usedin the actuator structural body according to the present invention;

FIG. 3 is a perspective view, partly omitted, of the actuator shown inFIG. 2;

FIG. 4 is a partial longitudinal cross-sectional view of the actuatorshown in FIG. 2;

FIG. 5 is a block diagram of a system for controlling the actuator shownin FIG. 2;

FIG. 6 is a partial longitudinal cross-sectional view of an end of theactuator shown in FIG. 2;

FIG. 7 is an exploded perspective view of a second embodiment of anactuator used in the actuator structural body according to the presentinvention;

FIG. 8 is an exploded perspective view of a pulley-combined inductionmotor in the actuator shown in FIG. 7;

FIG. 9 is an exploded perspective view of the pulley-combined inductionmotor in the actuator shown in FIG. 7;

FIG. 10 is an exploded perspective view of the pulley-combined inductionmotor in the actuator shown in FIG. 7;

FIG. 11 is a perspective view showing the relationship between a timingbelt and the pulley-combined induction motor in the actuator shown inFIG. 7;

FIG. 12 is a view illustrative of the manner in which a joint plate isinserted into a frame;

FIG. 13 is an exploded perspective view of a third embodiment of anactuator used in the actuator structural body according to the presentinvention;

FIG. 14 is an exploded perspective view of a pulley-combined inductionmotor in the actuator shown in FIG. 13;

FIG. 15 is an exploded perspective view of the pulley-combined inductionmotor in the actuator shown in FIG. 13;

FIG. 16 is an exploded perspective view of a fourth embodiment of anactuator used in the actuator structural body according to the presentinvention;

FIG. 17 is an exploded perspective view of a pulley-combined inductionmotor in the actuator shown in FIG. 16;

FIG. 18 is an exploded perspective view of the induction motor in theactuator shown in FIG. 16;

FIG. 19 is an exploded perspective view of the induction motor in theactuator shown in FIG. 16;

FIG. 20 is a perspective view of a first assembly of the actuatorstructural body according to the present invention;

FIGS. 21A and 21B are views illustrative of a first embodiment of ajoint means for joining an actuator and a columnar member in theactuator structural body according to the present invention;

FIG. 22 is a perspective view of the joint means shown in FIG. 21B;

FIG. 23 is a partly cross-sectional view of a second embodiment of thejoint means;

FIG. 24 is a partly cross-sectional view of a third embodiment of thejoint means;

FIG. 25 is a partly cross-sectional view of a fourth embodiment of thejoint means;

FIG. 26 is a perspective view of a fifth embodiment of the joint means;

FIG. 27 is a partly cross-sectional view illustrative of a joined stateof the joint means shown in FIG. 26;

FIG. 28 is a perspective view of the joint means shown in FIG. 26;

FIGS. 29A and 29B are views illustrative of a joined state of the jointmeans shown in FIG. 26;

FIG. 30 is a perspective view of a sixth embodiment of the joint means;

FIG. 31 is a partly cross-sectional view illustrative of a joined stateof the joint means shown in FIG. 30;

FIG. 32 is a perspective view showing a reinforcing member attached to ajoint of the actuator structural body;

FIG. 33 is a perspective view showing reinforcing members shown in FIG.32 that are attached in position;

FIG. 34 is a side elevational view of an end surface of a columnarmember used in the actuator structural body according to the presentinvention;

FIG. 35 is a side elevational view of an end surface of a columnarmember;

FIG. 36 is a side elevational view of an end surface of a columnarmember;

FIG. 37 is a side elevational view of an end surface of a columnarmember;

FIG. 38 is a side elevational view of an end surface of a columnarmember;

FIG. 39 is a perspective view of a seventh embodiment of the jointmeans;

FIGS. 40A and 40B are views illustrative of a joined state of the jointmeans shown in FIG. 39;

FIG. 41 is a perspective view of an eighth embodiment of the jointmeans;

FIGS. 42A and 42B are views illustrative of a joined state of the jointmeans shown in FIG. 41;

FIG. 43 is a perspective view of a ninth embodiment of the joint means;

FIGS. 44A and 44B are side elevational and longitudinal cross-sectionalviews illustrative of a joined state of the joint means shown in FIG.43;

FIG. 45 is a cross-sectional view showing a through hole in a columnarmember;

FIG. 46 is a cross-sectional view showing the through hole in thecolumnar member with wires, cables, and pipes inserted therein;

FIG. 47 is a cross-sectional view showing the through hole in thecolumnar member with an energy transmission passage provided therein;

FIG. 48 is a cross-sectional view showing the through hole in thecolumnar member with a ball spline and a spline nut inserted therein tocause the columnar member to function as a movable body;

FIGS. 49A through 49C are perspective views showing a tenth embodimentof the joint means;

FIGS. 50A and 50B are perspective and cross-sectional views showing aneleventh embodiment of the joint means;

FIG. 51 is a perspective view of a first embodiment of a balancer usedin the actuator structural body according to the present invention, thebalancer being housed in a frame with a drive table mounted thereon;

FIG. 52 is a front elevational view of the balancer shown in FIG. 51,with a cover opened;

FIG. 53 is a side elevational view, partly in cross section, of thebalancer shown in FIG. 52;

FIG. 54 is a cross-sectional view taken along line A--A across thebalancer shown in FIG. 53;

FIG. 55 is a cross-sectional view taken along line B--B across thebalancer shown in FIG. 53;

FIG. 56 is a cross-sectional view taken along line C--C across thebalancer shown in FIG. 53;

FIG. 57 is a cross-sectional view taken along line D--D across thebalancer shown in FIG. 53;

FIG. 58 is a schematic perspective view showing a clearance in thebottom of the frame;

FIG. 59 is a partly cross-sectional view showing a joined state of thebalancer and an actuator;

FIGS. 60A through 60E are schematic perspective views showing respectivecombinations of the balancer and the actuator;

FIG. 61 is a partly cross-sectional view of a second embodiment of thebalancer;

FIG. 62 is a partly cross-sectional view of a balancer and an actuatorthat are assembled together in a frame;

FIG. 63 is a front elevational view, partly cut away, of a balancer andan actuator that are juxtaposed, with a cover opened;

FIG. 64 is a transverse cross-sectional view of the balancer and theactuator shown in FIG. 63;

FIG. 65 is a front elevational view, partly cut away, of a balancer andan actuator that are juxtaposed, with a cover opened;

FIG. 66 is a transverse cross-sectional view of the balancer and theactuator shown in FIG. 65;

FIG. 67 is a front elevational view, partly cut away, of a balancer andan actuator that are juxtaposed, with a cover opened;

FIG. 68 is a transverse cross-sectional view of the balancer and theactuator shown in FIG. 67;

FIG. 69 is a perspective view of a conveyor device comprising aplurality of structural members joined and assembled together, with aworking table coupled thereto;

FIG. 70 is a perspective view of a conveyor device comprising aplurality of structural members joined and assembled together, with aconveying table coupled thereto;

FIG. 71 is a perspective view showing a first assembly of a plurality ofstructural members and actuators coupled thereto;

FIG. 72 is a perspective view showing a second assembly of a pluralityof structural members and actuators coupled thereto;

FIG. 73 is a perspective view showing a third assembly of a plurality ofstructural members and actuators coupled thereto;

FIG. 74 is a perspective view of a second assembly of the actuatorstructural body according to the present invention;

FIG. 75 is a partly perspective view of the actuator structural bodyshown in FIG. 74; and

FIG. 76 is a block diagram illustrative of operation of the actuatorstructural body shown in FIG. 74.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of an actuator structural body according to thepresent invention will be described in detail below with reference tothe accompanying drawings.

First, an actuator structural body will briefly be described withreference to FIG. 1. An actuator structural body A comprises columnarmembers B, actuators C, and a balancer D, each having a T-shaped groovedefined in an outer side surface thereof, which are connected by jointmeans (not shown), and a suction pad E is movably disposed in a desiredposition. The actuators C are operated to cause the suction pad E tomove a workpiece G on a working table F to a desired position.

The actuators, the joint means, and the balancer, which are componentsof the actuator structural body, will first be described, and theactuator structural body will finally be described.

A first embodiment of an actuator will be described below.

FIG. 2 is a perspective view of an actuator according to a firstembodiment, FIG. 3 is a perspective view, partly omitted, of theactuator shown in FIG. 2, FIG. 4 is a longitudinal cross-sectional viewof the actuator, and FIG. 5 is a block diagram of a system forcontrolling the actuator.

An actuator 10 according to the first embodiment has a table (movablebody) 16 disposed in an elongate frame (structural member) 18 fordisplacement along a linear guide 14 upon rotation of a ball screw shaft12, and two induction motors (hereinafter referred to as "motors") 20a,20b disposed as main and auxiliary motors, respectively, in the frame 18on respective opposite ends of the ball screw shaft 12 in confrontingrelationship to each other. The motors 20a, 20b are controlled by aninverter motor controller (hereinafter referred to as a "controller") 23through an encoder 21 that functions as a displacement detecting means.

More specifically, the actuator 10 has a frame 18, serving as an outerframe, with parallel grooves 24 of substantially T-shaped cross sectionbeing defined in side surfaces thereof except for a side surface with anopening 22, a linear guide 14 disposed on the bottom of the frame 18, abearing 26 slidable along the linear guide 14, the bearing 26 comprisingan endless circulating ball bearing, an endless circulating cross rollerbearing, a needle bearing, or a biological protein, a table 16 fixed tothe bearing 26 for linear displacement upon rotation of a ball screwshaft 12 that is fitted in a ball screw bushing 28, and motors 20a, 20bdisposed on respective opposite ends of the ball screw shaft 12 inconfronting relationship to each other, the motors 20a, 20b doubling asbearings for the ball screw shaft 12. The table 16 and the ball screwbushing 28 are preferably joined to each other by a swivel joint, anOldham joint, or the like, for example.

The frame 18 doubles as casings of the motors 20a, 20b, which haverespective stators 30a, 30b directly fixed to the frame 18 (see FIG. 4).The ball screw shaft 12 is integrally formed with motor shafts 32a, 32bof the motors 30a, 30b, which have respective cage rotors 34a, 34bmounted respectively on the motor shafts 32a, 32b. The motor shafts 32a,32b are rotatably supported by bearings 35a, 35b that are positioned atrespective opposite ends of the cage rotors 34a, 34b.

The cage rotors 34a, 34b may be directly coupled to the motor shafts32a, 32b as shown in FIG. 4. However, since the motor shafts 32a, 32band the ball screw shaft 12 are concentric with each other with highaccuracy, the motor shafts 32a, 32b may have spline grooves which arethe same as those of the ball screw shaft 12, and the cage rotors 34a,34b may be coupled to the spline grooves through a plurality of balls 36(see FIG. 6). For allowing the balls 36 to engage in the helical splinegrooves, the diameter of the balls 36 may be selected in order toincrease the accuracy with which the balls 36 and the spline grooves aremachined. The motor shaft with the spline grooves has externallythreaded outer circumferential portions 38 at the respective oppositeends of the cage rotor 34b in the axial direction thereof, and stoppers40a, 40b are fitted over the externally threaded outer circumferentialportions 38 to secure the cage rotor 34b in position. An end stopper 42is fitted over an end of the motor shaft with the spline grooves.Alternatively, cage rotors integrally formed by die casting, vacuum diecasting, or the like may be coupled to the ball screw shaft 12 byforce-fitting, staking, electron beam welding, or the like, or the cagerotors 34a, 34b may be integrally formed directly on the ball screwshaft 12 by die casting, vacuum die casting, or the like.

The angular displacement of the ball screw shaft 12 is detected by theencoder 21 that is mounted on an end of the ball screw shaft 12. Theencoder 21 preferably comprises an absolute encoder or anabsolute-signal-output integral encoder which comprises an integratingcounter memory, and has a sensor signal processor, a serial signalgenerator, etc. (not shown).

As shown in FIG. 5, the controller 23, which is positioned near themotor 20a, comprises a drive module 44, a control module 46, and acommunication interface 48. The communication interface 48 is connectedto an external device (not shown) through connectors 49a, 49b (see FIG.2).

The driver module 44 has drivers 50a, 50b for energizing the motors 20a,20b, a driver controller 52 for controlling the drivers 50a, 50b, and adistributor 54 which interconnects the drivers 50a, 50b and the drivercontroller 52. The drivers 50a, 50b effects inverter control on themotors 20a, 20b based on PWM or digital control.

The control module 46 manages an actuator operating program, andtransmits position and speed commands to the driver motor 44. Thecontrol module 46 also monitors feedback signals from the motors 20a,20b and the components of the driver module 44.

The communication interface 48 allows mutual communications between thecontrol module 46 and a LAN 56 or an external controller, a PC, acomputer, or a communication network represented by an Ethernet, a tokenring, a MAP, a PC LAN, a WAN, an OSI, or the like through a serialinterface represented by RS232C or RS422 or a parallel interfacerepresented by GP-IB, BCD, a Centronics parallel interface, or the like.

The components of the controller 23 may be of an integral structure fora reduced size. Alternatively, the components of the controller 23 maybe separable so that they can be shared by many types of actuators forversatility and low cost. For example, the control module 46 may beimplemented by an ASIC, a one-chip multi-CPU, a DSP, or the like forfully digitally performing control functions to achieve bothsophisticated functioning and low cost. Software switching may beemployed to control various induction motors, AC servomotors, DCservomotors, stepping motors, pneumatic actuators, and air balancerssingly and in combination, and also to perform end effector control,power control, position and speed control, multiaxis control such as forX-, Y-, Z-axes, θ, etc., and apparatus control such as for conveyors,lifters, etc. to achieve both sophisticated functioning and low cost.Controlled motors and corresponding interface format may be determinedfrom an impedance, a circuit configuration, or the like, or anidentification memory, a bar code, an ID tag, or the like based on thedata carrier technology, and automatically controlled by software. Thisallows a large amount of labor to be saved and results in an intelligentsystem when a network or a line is constructed. Signals may betransmitted over power supply lines connected to the motors, so that alarge number of signal lines can be saved. Active noise control may berelied upon to process noise produced by the actuators.

The encoder 21 and the controller 23 have respective casings that areprovided by the frame 18. However, these casings and the frame 18 may beseparate from each other depending on the arrangement of the actuator10. The separate casings and frame 18 may be interfitted by circular orpolygonal fitting members or pins, and electric power lines, signallines, a bus, a LAN, and sensors may be connected by connectors at thesame time, and the joined components may be fixed to each other bystaking, electron beam welding, or the like. Alternatively, thecontroller and the motors may be constructed as modules, and may beadded or removed as required.

The above structural details of the actuator 10 are realized by themotors 20a, 20b which are simple in structure. The simplified actuator10 is low in cost and compact in structure.

The linear guide 14 and the ball screw shaft 12 are equivalent to a camfollower or a sliding guide made of a self-lubricating material such aspolyimide, Teflon, nylon, polyacetal, or the like, and a timing belt, awire rope, or a perforated metallic belt made of SUS 301, 304, 430,63SK, phosphor copper, nickel, or the like.

The actuator 10 may employ a single induction motor, rather than theseparate induction motors, for a further structural simplification. Itis preferable to improve the holding capability of the actuator at thetime it is stopped, with a hydraulic, pneumatic, electromagnetic,piezoelectric, or electric brake system. Braking members of the brakesystem should preferably be made of a heat-resistant material such asCFRP, ceramics, or the like.

The actuator 10 according to the first embodiment, which is of the basicstructure described above, operates as follows:

Drive forces produced by the two motors 20a, 20b, as the main andauxiliary motors, are transmitted through the ball screw shaft 12 to theball screw bushing 28, which converts the rotary motion of the ballscrew shaft 12 into linear motion for thereby displacing the table 16.

For normally actuating the table 16, the main and auxiliary motors 20a,20b produce drive forces in the same direction. Therefore, the actuator10 produces an output power which is equal to the sum of the driveforces produced by the motors 20a, 20b.

When the table 16 is decelerated while it is being displaced, one orboth of the main and auxiliary motors 20a, 20b operate as an inductionbrake. If a greater deceleration is required, it is necessary to causeboth the motors 20a, 20b to positively generate a decelerating torque.When the table 16 is stopped, the motors 20a, 20b can be controlled togenerate opposite torques for thereby holding the table 16 stopped underthe differential force to position the table 16 highly accurately.

If a rotary actuator incorporates an induction motor, then it ispossible to construct an integral articulation, and the rotary actuatorcan be greatly reduced in size and weight. For a rotary actuator havinga plurality of articulations or a multiaxis actuator having X-, Y-,Z-axes, the weight of a drivable component largely affects the speed andacceleration of the actuator. If a relatively light induction motor isemployed, it is possible to increase the accuracy of the abovepositioning, speed, acceleration, etc.

An actuator according to a second embodiment in which a timing belt 90is used as a power transmitting means and a timing belt pulley and aninduction motor are integral with each other will be described withreference to FIGS. 7 through 12. Those components of the embodimentdescribed below which are identical to those of the first embodiment aredenoted by identical reference numerals, and will not be described indetail.

As shown in FIG. 7, an actuator 70 comprises a frame 72 serving as astructural member, a drive mechanism 76 having pulley-combined inductionmotors (hereinafter referred to as "motors") 74a, 74b as main andauxiliary motors, and a joint plate 78 by which the drive mechanism 76is joined in the frame 72. A controller 23 for controlling the drivemechanism 76 is disposed closely to the motor 74a.

The frame 72 is formed of a light metal such as an alloy of Al, Mg, orthe like or a bearing steel by extrusion or drawing, or of a metal, aceramic material, or the like by injection molding, vacuum casing, or alost-wax process. If necessary, a cladding layer may be formed on aninner wall surface of the frame 72 by explosion, thereby to achieve adesired surface hardness on the frame 72. The frame 72 has grooves 24 ofsubstantially T-shaped cross section being defined in three outersurfaces thereof for joining other frames, panels, or the like orhousing leads or the like therein. The frame 72 has an opening 80 whichhouses therein the drive mechanism 76, the controller 23, and the jointplate 78. The frame 72 also has slots 82 defined in the bottom thereoffor joining and fixing the drive mechanism 76, one of the slots 82having a clearance 84 for allowing the joint plate 78 to be insertedeasily from the opening 80 in the frame 72 (see FIG. 12).

The drive mechanism 76 has a base plate 86 which supports the motors74a, 74b mounted thereon at its opposite ends in confrontingrelationship to each other with a guide rail 88 extending between themotors 74a, 74b, a timing belt 90 trained around the motors 74a, 74bthat are spaced a given distance from each other, a belt holder 92 forholding the timing belt 90, a table 94 that is linearly displaceable inresponse to angular movement of the timing belt 90 which is held by thebelt holder 92, and a guide block 96 interposed between the guide rail88 and the table 94. The base plate 86, the motors 74a, 74b, and theguide rail 88 are connected to each other by screws (not shown), but maybe interconnected by T bolts or the like received in a T slot or thelike defined in the base plate 86. The motors 74a, 74b disposed on theopposite ends of the base plate 86 in confronting relationship to eachother will be described below. Since the motors 74a, 74b aresubstantially identical in structure to each other, only the motor 74awill be described in detail, and the other motor 74b will not bedescribed in detail.

As shown in FIGS. 8 through 10, the motor 74a basically comprises anouter frame 98 of substantially channel-shaped cross section, a rotorassembly 100 rotatably mounted in the outer frame 98, and fixing members104a, 104b for fixing the rotor 100 to the outer frame 98 through screws102.

The rotor assembly 100 comprises a substantially cylindrical firsthousing 106 having an opening, and a disk-shaped second housing 108connected to the first housing 106 over the opening thereof. The firsthousing 106 has, on its outer circumferential surface, teeth 110 fordriving the timing belt 90, flanges 112, 113 for preventing the timingbelt 90 from being dislodged, and an encoder rotor 114 for enabling anencoder sensor 115 to detect an angular displacement of the rotorassembly 100 with light, magnetism, a CCD-PICKUP, laser, or the like.The first housing 106 has a bearing-fixing hole (not shown) defined inan inner bottom surface thereof, and the outer circumference of abearing 116 is fixedly disposed in the bearing-fixing hole. A rotor 118is disposed on an inner circumferential surface of the first housing 106and fixed in surrounding relationship to a stator 122 that is supportedon a fixed shaft 120. The second housing 108 has an externally threadedouter circumferential surface 126 which is threadedly fitted in aninternally threaded surface 124 in the opening of the first housing 106,so that the first and second housings 106, 108 are fastened to eachother.

Leads of the stator 122 extend through the fixed shaft 120 out of an endof the fixed shaft 120. The fixed shaft 120 has flanges on itsrespective opposite portions, and a pair of bearings 116 such as crossroller bearings, angular bearings, Ex-Cell-O bearings, conical rollerbearings, or the like is positioned on the flanges in confrontingrelationship to each other. The fixed shaft 120 has opposite ends eachhaving a substantially square cross section for preventing the rotorassembly from rotating when it is mounted on the motor frame.

The motors 74a, 74b, which are of the basic structure described above,are fixed to the respective outer frames 98 by the fixing members 104a,104b that engage the opposite ends of the fixed shaft 120 which eachhave a substantially square cross section. When the motors 74a, 74b areenergized, the first and second housings 106, 108 are rotated to causethe teeth 110 to drive the timing belt 90. The encoder sensor 115 ismounted on the outer frame 98 for detecting the angular displacement ofthe motor in coaction with the encoder rotor 114 on the outercircumferential surface of the first housing 106.

The joint plate 78 and the base plate 86 are formed of a light metalsuch as an alloy of Al, Mg, or the like or a bearing steel by extrusionor drawing, or of a metal, a ceramic material, or the like by injectionmolding, vacuum casing, or a lost-wax process. The base plate 86 has alongitudinal groove 130 (see FIG. 7) for positioning the guide rail 88when it is attached. The base plate 86 and the guide rail 88 may beintegrally formed of bearing steel or the like, with the guide railbeing ground at its sliding surface by electrolytic grinding, chemicalgrinding, or the like, or may be made of a light metal such as an alloyof Al, Mg, or the like or a ceramic material by extrusion, drawing,vacuum die casting, a lost-wax process, or metallic or ceramic injectionmolding, with bearing steel joined to a sliding surface of the guiderail. The base plate 87 has attachment holes 132 defined therein forjoining itself to the joint plate 78.

The timing belt 90 which serves as a power transmitting member transmitsrotative forces generated by the motors 74a, 74b to the table 94. Thepower transmitting member may alternatively comprise a fitting steelbelt, a chain, a wire rope, or the like. If it is necessary to positionthe table 94 with accuracy, then a synchronous transmitting mechanismsuch as a chain or the like is preferable as the power transmittingmember. As shown in FIG. 11, the timing belt 90 has belt teeth 134 heldin mesh with the teeth 110 of the motors 74a, 74b, and a longitudinalridge 136 on its center to prevent the timing belt 90 from movingtortuously and also from being worn at its sides. If the timing belt 90is made of polyurethane, then it is possible for the timing belt 90 toprevent dust from being produced. Dust produced by movable elementsincluding the power transmitting members, the motors 74a, 74b, thelinear guide, etc. is prevented from being scattered around because thecomponents are housed and sealed in the frame 72. If air in the isdischarged out by positively evacuating the frame, then the actuatorlends itself to use in the fabrication and precision experimentation ofsemiconductors or the like in a clean room, and the biological orchemical experimentation of genes of the like.

The table 94 is formed of a light metal such as an alloy of Al, Mg, orthe like or a bearing steel by extrusion or drawing, or of a metal, aceramic material, or the like by injection molding, vacuum casing, or alost-wax process. The table 94 has screw holes 138 for attaching aworkpiece thereto and holes 140 for attaching and positioning aworkpiece thereon, the holes 138, 140 being defined on opposite sidesthereof. A magnet (not shown) is coupled to the table 94, and sensorsinserted in the grooves 24 of substantially T-shaped cross section whichare defined in the side surfaces of the table 94 detects magnetic fluxesfrom the magnet for detecting the position of the table 94. The sensormay function simply as a limit switch, or a linear magnetic encoder, alinear optical encoder, or the like may be employed to detect theposition of the table 94 more accurately to produce position and speedfeedback information. In such a case, the encoder 21 for detecting therotational speed of the motors 74a, 74b in the first embodiment does notneed to be provided, and the position and speed can be controlled withincreased accuracy because the power transmitting system including theball screw, the timing belt, etc. is contained in the feedback loop.

The timing belt 90 is coupled to the table 94 by fixing opposite ends ofthe timing belt 90, together with the belt holder 92 which is shapedcomplementarily to the belt teeth 34 of the timing belt 90, to the sidesof the table 94 with screws, staking, or the like.

The guide rail 88 is joined to the upper surface of the base plate 86,serving as a coupling member, by bolts. The guide block 96 is movable asa rolling guide on the guide rail 88 through balls, cylindrical rollers,cross rollers, or the like interposed therebetween. The linear guide maycomprise, other than the rolling guide, a sliding plane guide having aguide rail and a guide block which are made of a low-friction,self-lubricating material such as polyimide, Teflon, nylon, polyacetal,or the like. Alternatively, the movable components such as the table,etc. may be formed partly or wholly of such an alloy or resin.Similarly, the guide rail 88 and the base plate 86 as a coupling membermay be integrally formed with each other.

The motors 74a, 74b and the power transmitting members such as thetiming belt 90, etc. are generally connected to each other by beltdriving pulleys (not shown) connected to the drive shafts of the motors74a, 74b for transmitting drive forces from the motors to the timingbelt 90. However, the belt driving pulleys connected to the drive shaftsof the motors 74a, 74b would tend to increase the overall length of themotors 74a, 74b and the drive shafts thereof, causing the motors 74a,74b to project from the frame 72. In order to house the motors 74a, 74bwithin the frame 72 without projecting from the outer side surfaces ofthe frame 72, orthogonal means would be required between the motors 74a,74b and the rotatable shafts of the belt driving pulleys, resulting in acomplex structure. According to the present invention, therefore, themotors 74a, 74b comprise induction motors of simple structure, and aremade integral with the belt driving pulleys, so that the drive unit isrendered small in size. With such a simple arrangement, the motors 74a,74b are housed in the frame 72 such that they do not project from theouter side surfaces of the frame 72, but have surfaces lying flush withthe outer side surfaces of the frame 72. However, the motors 74a, 74bmay be used such that they project from the outer side surfaces of theframe 72.

In this embodiment, the two main and auxiliary motors 74a, 74b arecontrolled by the controller 23, and may be superimposed by the frame 72as with the first embodiment. However, the main and auxiliary motors74a, 74b may be housed as blocks in the frame 72. The structure andoperation of the controller 23 are the same as those of the controlleraccording to the first embodiment, and will not be described in detailbelow.

A third embodiment is illustrated in FIGS. 13 through 15. An actuator150 according to the third embodiment has a timing belt 90a as a powertransmitting means and motors 152a, 152b, as with the second embodiment,which make up a small-size power unit. Those components which correspondto those of the second embodiment are denoted by identical referencenumerals with a suffix "a", and will not be described in detail below.

The actuator 150 comprises a frame 154 serving as a structural member,and a drive mechanism 157 having a table 156 that is displaceable by thetiming belt 90a which is moved by the motors 152a, 152b.

The table 156 is formed of a light metal such as an alloy of Al, Mg, orthe like or a bearing steel by extrusion or drawing, or of a metal, aceramic material, or the like by injection molding, vacuum casing, or alost-wax process. Linear guide bearings 158, 159 disposed in the bottomof the table 156 substantially parallel to each other are in the form ofhollow cylinders that are partly open, and the hollow cylinders have aplurality of passages defined in their inner surfaces which accommodatesteel balls held in rolling contact with two guide shafts 160, 161 forendless circulatory motion. The linear guide bearings 158, 159 may bereplaced with a plane guide made of a low-friction, self-lubricatingmaterial such as polyimide, Teflon, nylon, polyacetal, or the like.Alternatively, the table 156 may be formed partly or wholly of such amaterial.

As shown in FIG. 14, each of the motors 152a, 152b comprises a firstfixing member 164, a second fixing member 166, and a rotor assembly 100afixed to the first and second fixing members 164, 166 by screws 162. Thefirst and second fixing members 164, 166 have recesses 168, 169 whichsupport therein fixed shafts 120a, 120b at the opposite ends of therotor assembly 100a. Operation and advantages of the actuator accordingto the third embodiment are the same as those of the actuator accordingto the first embodiment, and will not be described in detail below.

FIGS. 16 through 19 show a fourth embodiment. An actuator 170 accordingto the fourth embodiment has a ball screw shaft 17 as a powertransmitting means and motors 174a, 174b, which make up a small-sizepower unit. Those components which correspond to those of the secondembodiment are denoted by identical reference numerals with a suffix"b", and will not be described in detail below.

The actuator 170 comprises a frame 176 serving as a structural member,and a drive mechanism 180 having a table 178 that is displaceable by theball screw shaft 172 which is rotated by the motors 174a, 174b.

The drive mechanism 180 is fixed to the bottom of the frame 176 by ajoint plate 182, and a base plate 184 is joined to an upper surface ofthe joint plate 182. A guide rail 186 is fastened to an upper surface ofthe base plate 184. The base plate 184 and the guide rail 186 may beintegrally formed with each other.

The table 178 is fixedly mounted on a guide block (not shown) whichmoves linearly on the guide rail 186. A ball screw nut 188 is secured tothe table 178, and the ball screw shaft 172 is threadedly fixed in theball screw nut 188. The ball screw shaft 172 and the ball screw nut 188convert rotative drive forces from the motors 174a, 174b into lineardrive forces for linearly displacing the table 178. The axis of the ballscrew nut 188 is positioned out of alignment with the axis of the guiderail 186 to reduce the height of the table 178. The axes of the ballscrew shaft 172 and the guide rail 186 are spaced from the central axisof the actuator 170.

Generally, the ball screw shaft 172 and the motors 174a, 174b areconnected to each other by an Oldham joint, a flexible joint, auniversal joint made of rubber or the like that is positioned betweenends of the ball screw shaft 172 and ends of the shafts of the motors174a, 174b. Alternatively, the ball screw shaft 172 and the motor shaftsmay be made integral with each other using the motors 20a, 20b indicatedby the first embodiment. With the axis of the ball screw shaft 172spaced from the central axis of the actuator 170, however, the motors174a, 174b whose shafts are aligned with the ball screw shaft 172 wouldproject from the upper surface of the frame 176. To prevent the motors174a, 174b from projecting from the frame 176, it is customary to spacethe axis of the ball screw shaft 172 from the axes of the motor shafts,and connect the ball screw shaft 172 and the motor shafts with gears.Such an arrangement, however, result in a complex power unit structure.According to this embodiment, the axis of the ball screw shaft 172 isspaced from the axes of the motor shafts, the ball screw shaft 172 andthe motor shafts are connected by timing belts 190, and pulley-combinedinduction motors are employed, as with the second and third embodiments,resulting in a small-size, simple power unit.

The motors 174a, 174b are supported by respective fixing members 166bwhich hold respective ends of the ball screw shaft 172 through bearings(not shown). Driven pulleys 192 are connected to the respective ends ofthe ball screw shaft 172 for transmitting rotational drive forces fromthe motors 174a, 174b to the ball screw shaft 172 through the timingbelts 190.

In the actuators 70, 150, 170 according to the second through fourthembodiments, respectively, induction motors and drive pulleys are madeintegral with each other based on the simple structure of the inductionmotors, resulting in a small-size drive unit, and the motors are housedin the frame without projecting from the outer side surfaces of theframe. The actuators 70, 150, 170 have the grooves 24 of substantiallyT-shaped cross section defined in their outer surfaces for allowingthemselves to be incorporated in production lines in factories or thelike, and are also compatible with each other. Consequently, theactuators 70, 150, 170 can be used to install thereon frames and panelsof other actuators, protective metal screens, handrails, etc., and alsoto secure thereto wires, pipes, solenoid-operated valves, ejector unitswith solenoid-operated valves, and their manifolds. As a results, theframes of the actuators 70, 150, 170 can be used as structural membersfor constructing an actuator structural body (described later on), andcan easily be incorporated into an actuator structural body withoutusing conventional beams, panels, or the like for attachment. When theattached position of an actuator needs to be changed in an actuatorstructural body which has been constructed, it has heretofore beennecessary to change the position of a beam or drill a hole again in apanel with conventional actuators. According to the present invention,however, it is only necessary to loosen attachment bolts as fasteningmembers, moving the actuator a required distance in the frame, andthereafter tighten the attachment bolts again. Therefore, the process issimple and can be carried out in a smaller number of steps. In the eventof a trouble or an inspection for maintenance, since the actuator caneasily be removed from the actuator structural body, the inspectionprocess can efficiently be carried out. The actuator can also bereplaced with another actuator for a quick servicing process. Since aplurality of actuators can be assembled in a single elongate frame, thecombination of actuators can be made compact.

A plurality of actuators and an air balancer which are coupled togetherinto an actuator structural body will be described below.

As shown in FIG. 20, a first assembly of an actuator structural body 200comprises a plurality of columnar members (structural members) 202 whichconstitute a skeleton, first through fourth actuators 204, 206, 208,210, an air balancer (hereinafter referred to as a "balancer") 212associated with the second actuator 206, a working table 214, workpieces216, a workpiece storage box 218, a workpiece holder plate 220, movablebodies 222, 224, 226, 228, a cylinder 232 to which a suction pad 230 asa workpiece gripping means is coupled, a cylinder 236 having a cylinderrod 234 as it projects, electric actuator control boxes 238, a filterregulator lubricator controller 240, and other non-illustratedcomponents including a compressor, a dehumidifier, an after-cooler, etc.The actuators 204, 206, 208, 210 shown in FIG. 20 are of a basicstructure which is identical to that of the actuators according to thefirst through fourth embodiments described above.

The non-illustrated components including a compressor, a dehumidifier,an after-cooler, etc. are assembled in an integral structure andinserted in the blocks of the actuators 204, 206, 208, 210. In thisarrangement, they are integrally arranged or connected and wired in thecolumnar members. It is possible to employ a suction device such as aknown compressor, a scroll compressor, or the like to circulate a vacuumpressure for use. The compressor, the dehumidifier, the after-cooler,the known compressor, the scroll compressor, etc. may be dispersed andhoused in motor boxes of the actuators, valve units, or the like.

The first actuator 204 serves to linearly move the second actuator 206and the balancer 212 which are mounted on an upper surface of themovable body 222. The second actuator 206 connected perpendicularly tothe first actuator 204, and the balancer 212 associated with the secondactuator 206 serve to vertically move the third actuator 208 mounted onthe movable body 224. The cylinder 232 with the suction pad 230connected thereto is joined to the movable body 226 disposed on thethird actuator 208 which is connected perpendicularly to the secondactuator 206 and the balancer 212 associated with the second actuator206. The cylinder 236 is joined to the movable body 228 disposed on thefourth actuator 210 for conveying and positioning the workpieces 216. Amotor box 242 is disposed at a junction between the first actuator 204and the columnar member 202, and a valve unit 244 is disposed at ajunction between the fourth actuator 210 and the columnar member 202.The motor box 242 and the valve unit 244 may be shaped so as to lieflush with the upper surfaces of the first and fourth actuators 204,210, without projecting therefrom. Some of the electric actuator controlboxes 238 may be dispersed and housed in the motor box 242 and the valveunit 244.

The actuator structural body 200 operates as follows: Compressed air issupplied through fluid passages in the columnar members 202 to thecylinder 232 coupled to the third actuator 208. When the compressed airis supplied, the cylinder rod of the cylinder 232 is displaceddownwardly, and the suction pad 230 attracts a workpiece 216 in theworkpiece storage box 218. Compressed air is supplied again to displacethe cylinder rod upwardly, and while the cylinder rod is being displacedupwardly, the movable body 224 on the balancer 212 which is associatedwith the second actuator 206 is moved upwardly, therebymoving the thirdactuator 208 upwardly. The movable body 222 on the first actuator 204 ismoved to move the second actuator 206 connected to the movable body 222and the balancer 212 associated with the second actuator 206. The firstactuator 204 and the third actuator 208 stop moving when the workpiece206 attracted by the suction pad 230 has moved near a position above adesired position. The movable body 224 on the second actuator 206 andthe balancer 212 associated therewith, and the cylinder rod of thecylinder 232 are lowered to insert the workpiece 216 into a hole 246defined in the workpiece holder plate 220. At this time, the cylinderrod 234 of the fourth actuator 210 can be displaced to position theworkpiece 216 in the hole 246. The fourth actuator 210 can convey theworkpiece 216 to the working table 214 with the movable body 238 and thecylinder 236. The workpiece storage box 218 and the workpiece holderplate 220 are positioned on the working table 216 by a positioning means(not shown).

Joint means for connecting the columnar members 202, the actuators 204,206, 208, 210, the balancer 212, etc. will be described below withreference to FIGS. 21A, 21B through 25.

FIGS. 21A, 21B, and 22 show a first embodiment of the joint means. FIG.21A is a fragmentary front elevational view of columnar membersconnected to each other, FIG. 21B is a side elevational view, partly incross section, of the connected columnar members shown in FIG. 21B, andFIG. 22 is an exploded perspective view of the joint means.

In FIGS. 21A and 21B, each of columnar members 248 which aresubstantially identical to each other has linear grooves 250 definedlongitudinally in side surfaces thereof. A plate 254 which can besecured by a screw 252 is slidably disposed in one of the grooves 250.The screw 252 has a conical tip 256. Each of the columnar members 248has fluid passages 258 serving as passages for delivering a fluid suchas air, oil, water, or the like, which are defined in respective fourcorners thereof, and a hole 264 defined substantially centrally thereinfor inserting a bolt 262 with a spring 260. The bolt 262 has a head 266shaped complementarily to the cross-sectional shape of the grooves 250.The head 266 is loosely fitted substantially perpendicularly into one ofthe grooves 250 from one end of the columnar member 248. The bolt 262also has a V-shaped notch 268 defined in an intermediate portionthereof, and a circular recess 270 defined in an end thereof remote fromthe head 266 for receiving the spring 260.

For connecting the columnar members 248 to each other, the plate 254 isinserted into one of the grooves 250 from an end of one of the columnarmembers 248, and the spring 260 and the bolt 262 is insertedlongitudinally into the hole 264 of the columnar member 248. The head266 of the bolt 262 is loosely fitted substantially perpendicularly intoone of the grooves 250 at one end of the other columnar member 248.Then, the screw 252 is threaded through the groove 250 into the plate254. The columnar members 248 are now fixedly connected substantiallyperpendicularly to each other by the bolt 262. Specifically, as shown inFIG. 21B, a slanted surface of the tip 256 of the screw 252 is broughtagainst a slanted surface of the V-shaped notch 268, displacing the head266 of the bolt 262 in the direction indicated by the arrow A. Thedisplacement of the head 266 causes the reverse side of the head 266that is loosely fitted in the groove 250 to be held against surfaces ofthe groove 250, thus securing the columnar members 248. In this manner,the columnar members 248 can easily be joined to each other, and itbecomes possible to transmit a fluid pressure signal through the fluidpassages 258 in the columnar members 248.

For disconnecting the columnar members 248 from each other, the screw252 is loosened, allowing the bolt 262 to be displaced in the directionindicated by the arrow B under the resiliency of the spring 260. Upondisplacement of the bolt 262, the reverse side of the head 266 is spacedfrom the surfaces of the groove 250, and the head 266 is again looselyfitted in the groove 250. With the head 266 being loosely fitted in thegroove 250, the head 266 of the bolt 262 which has been inserted fromone of the columnar members 248 into the other can be slidingly moved inthe groove 250. The other columnar member 248 can thus be removed bymoving itself along the groove 250. The first embodiment of the jointmeans has been described with respect to the joining of the columnarmembers 248. However, the joint means may be used to join a columnarmember 248 and any of the actuators 204, 206, 208, 210 or the balancer212 to each other, though details of such joining will not be described.

A second embodiment of the joint means shown in FIG. 23 differs from theabove embodiment in that parallel grooves 250 are defined in respectiveside surfaces of a columnar member 272, and there are disposed two bolts278 integral with heads 276 loosely fitted in the grooves 250. Thoseparts of the second embodiment and other embodiments of the joint meanswhich are substantially identical to those of the first embodiment aredenoted by identical reference numerals, and will not be described indetail below.

According to third and fourth embodiments of the joint means shown inFIGS. 24 and 25, columnar members are joined to each other in threedirections that extend substantially perpendicularly to each other. Inthe third embodiment shown in FIG. 24, columnar members 248 according tothe first embodiment of the joint means are connected to respective sidesurfaces of the balancer 212 and the second actuator 206 shown in FIG.20, and a columnar member 272 is connected substantially perpendicularlyto the columnar members 248 across respective frames 280, 282 of thebalancer 212 and the second actuator 206 by two bolts 262 whichcorrespond to respective parallel grooves 250 defined in the bottoms ofthe frames 280, 282. In the fourth embodiment shown in FIG. 25, columnarmembers 248, 286 are joined respectively to an actuator 284 and thebalancer 212 associated therewith. Further details of the fourthembodiment will not be described below.

A fifth embodiment of the joint means will be described below withreference to FIGS. 26 through 28.

FIG. 26 is a perspective view of the joint means and a columnar member,FIG. 27 is a partly cross-sectional view of columnar members joined bythe joint means, and FIG. 28 is a perspective view of the columnarmembers joined by the joint means.

In FIG. 26, a connecting block (hereinafter referred to as a "connectingblock") 290 connected to an end of a columnar member 288 which is cutsubstantially perpendicularly to the longitudinal direction thereof isformed by die casting or precision casting, preferably vacuum diecasting, vacuum casting, a lost-wax process, extrusion, drawing,metallic powder injection molding, or ceramic forming. The block 290 hasa substantially cylindrical protrusion 292 disposed substantiallycentrally on a surface thereof which is to be joined to a columnarmember 288. The protrusion 292 is fitted with a fitting dimensionaltolerance in a through hole 294 which is defined axially in one ofcolumnar members 288 to be joined to each other, the through hole 294serving as a fluid passage. Therefore, even if the end of the columnarmember 288 is not cut perpendicularly to the longitudinal directionthereof, since the protrusion 292 extends perpendicularly to thecontacting surface of the block 290 and the through hole 294 extendsparallel to the longitudinal direction of the columnar member 288, thecontacting surface of the block 290 is corrected into a position inwhich it lies perpendicularly to the longitudinal direction of thecolumnar member 288.

The block 290 has teeth 296a˜296d disposed in facing pairs andsurrounding the protrusion 292. The teeth 296a˜296d have respectivesubstantially circular holes 298a˜298d defined therein. The teeth296a˜296d are inserted into respective grooves 300 of substantiallyT-shaped cross section in the columnar member 288, and setscrews 302 arethreaded through the respective holes 298a˜298d into biting engagementwith inner portions 304 of the grooves 300, causing elastic deformationor plastic deformation, preferably plastic deformation, for securingconnecting the block 290 to the columnar member 288. Since tip ends 305of the teeth 296a˜296d spread outwardly in directions opposite to thedirections in which the setscrews 302 are threaded, the setscrews 302are forced to bite into the inner portions 304 for securely preventingthe block 290 from being dislodged from the columnar member 288 (seeFIG. 28). To prevent the block 290 from being displaced due to differentdistances by which the setscrews 302 are threaded in, the protrusion 292is inserted in the through hole 294, and the teeth 296a˜296d on the endsurface of the block 290 are inserted longitudinally into the respectivegrooves 300 in the columnar member 288. The block 290 can thus reliablybe positioned with respect to the columnar member 288.

A substantially T-shaped bolt 306 and a spring 308 are inserted into theblock 290 attached to the columnar member 288, and a head 310 of thebolt 306 is inserted longitudinally into a companion columnar member 288to be connected and then turned about 90° to prevent the bolt 306 frombeing removed from the companion columnar member 288. The bolt 306 issecurely held in position by a setscrew 312 against angular movement orwobbling movement under the bias of the spring 308, so that the block290 is reliably and easily joined to the columnar member 288 (see FIG.27). When the setscrew 312 is loosened for removing the block 290 fromthe joined companion columnar member 288, the bias of the spring 308acts in a direction to move the bolt 306 away from a surface of thecompanion columnar member 288, which can easily be removed forreconstruction.

Plastic deformation or elastic deformation, preferably elasticdeformation, of a portion of the columnar member 288 connected to thehead 310 of the bolt 306 inserted in the block 290 will be describedwith reference to FIGS. 29A and 29B. When the bolt 306 is inserted intothe block 290, a reverse side 314 of the head 310 of the bolt 306 isheld against a flat surface 316 of the groove 300 of substantiallyT-shaped cross section. Another surface of the columnar member 288 whichis opposite to the flat surface 316 and held against the block 290 has astep 318 which allows edges 320 to be deformed against the block 290when the reverse side 314 of the head 310 presses the flat surface 316.

A sixth embodiment of the joint means for joining columnar members 288as shown in FIGS. 30 and 31 will be described below.

A rectangular block 324 is fastened to the surface of a cut end of acolumnar member 288 by four self-tapping screws 322 with hexagonalsockets. The rectangular block 324 has a through hole 326 definedtherein. When a bolt 328 and a spring 330 are inserted into the columnarmember 288 through the through hole 326 and a setscrew 332 is threadedinto the rectangular block 324, the columnar member 288 and anothercolumnar member 288 are joined to each other. When the columnar members288 are to be joined to each other, the bolt 328 is required to bepressed against the bias of the spring 330, preventing a notch in thebolt 328 from being angularly displaced or wobbling. The spring 330 alsoserves to cause the bolt 328 to move the columnar members 288 away fromeach other when the setscrew 332 is loosened again after the columnarmembers 288 have been joined to each other.

The rectangular block 324 has holes 334 defined in respective fourcorners thereof for receiving the respective self-tapping screws 322with hexagonal sockets. The through hole 294 defined substantiallycentrally in the columnar member 288 and opening at an end surfacethereof is used as a fluid passage for transmitting any of variousfluids such as compressed air. A gasket groove which will be difficultto machine subsequently is defined in the end surface of the columnarmember 288 which faces the block 324, and then sealed. With a sheet-likegasket being used in the gasket groove, the junction between thecolumnar member 288 and the block 324 is prevented from being lowered inrigidity and the structural member is prevented from sufferingdimensional changes when it is joined, and any of various fluids in thecolumnar member 288 is prevented from leaking and the fluid can flowinto and out of the opening of the through hole 294 at the end surfaceof the columnar member 288. Gasket grooves and seal members may beprovided between the columnar member 288, the rectangular block 324, andanother columnar member 288 join ed thereto, so that fluid passages maybe established in those columnar members 288.

A structural body comprising a plurality of columnar members 336 withreinforcing members or other columnar members attached thereto will bedescribed below.

As shown in FIGS. 32 and 33, bolts 338 are inserted in grooves 300 ofsubstantially T-shaped cross section which are defined in side surfacesof columnar members 336. At this time, longer sides 339 of heads 337 ofthe bolts 338 are inserted longitudinally into the grooves 300, andthereafter the heads 337 are turned about 900° for protection againstangular displacement, so that the bolts 338 are fixedly mounted in thegrooves 300 at desired positions therein. After the bolts 338 have beenfixedly mounted in the grooves 300 in the side surfaces of the columnarmembers 336, reinforcing members 340, 341, 342, 343 shapedcomplementarily to respective the junctions are fastened by nuts 344threaded over the bolts 338. When the bolts 338, the reinforcing members340, 341, 342, 343, etc. are used, the joints of the constructedstructural body are reinforced, increasing the overall rigidity of thestructural body. The accuracy of the structural body in use at the timeactuators, etc. are connected is prevented from being reduced, and othercolumnar members 336, etc. may be joined for easily expanding theequipment.

End surfaces of other various columnar members are shown in FIGS. 34through 38.

FIGS. 34 through 36 show respective columnar members 346, 348, 350 whichare suitable for use in regions where strong loads are applied, of astructural body which has been assembled to desired configuration. FIGS.37 and 38 show respective columnar members 352, 354 which are made lightin weight by spaces defined therein. The columnar members 346, 348, 350,352, 354 are formed of a light metal such as aluminum alloy, magnesiumalloy, aluminum, silicon, or the like, and are surface-treated by anoxide coating (Alumite coating), a hard oxide coating (hard Alumitecoating), a titanium coating, a cermet coating, a PVD coating, a CVDcoating, or the like for increasing their mechanical strength andreducing scratches which will be produced on their surfaces when variousmembers are attached thereto or detached therefrom. The columnar members346, 348, 350, 352, 354 may be colored by a paint coating, or preferablya colored oxide coating (Alumite coating), for equipment identificationor insulation.

Each of the columnar members may be marked with data, such as a barcode, representing a serial number, a date, a product number, a length,a manufacturer, a selling company, a user, etc. by laser trimming, inkjet printing, or the like. When the columnar members are installed, thedata are registered in computer data bases associated with conveying,machining, and assembling equipment. Therefore, the columnar members andactuators that belong to all the equipment used in coordinatedproduction such as CIM or the like can easily be managed. At the timethe equipment is modified or expanded, the data in the CIM data base caneasily be reconstructed.

A seventh embodiment of the joint means is shown in FIGS. 39 and 40A,40B. Those components of embodiments described below which are identicalto those of the seventh embodiment are denoted by identical referencenumerals, and will not be described in detail.

As shown in FIG. 39, for joining columnar members 356 to each other, aconnecting block 358 is attached to the surface of a cut end of one ofthe columnar members 356. The connecting block 356 has a protrusion 364inserted in a substantially central through hole 360 defined in thesurface of the cut end of the columnar member 356. The protrusion 364has a plurality of slits 362a˜362f defined therein. The slits 362a˜362fdivide the protrusion 364 into a plurality of arms which have respectiveteeth 366a˜366f on the outer circumferential surfaces of their tip ends.The connecting block 356 also has joint pins 368 disposed respectivelyon its four corners in the vicinity of the protrusion 364. Theconnecting block 356 further has a hole 373 defined in a side surfacethereof remote from the protrusion 364 for inserting therein a bolt 372of substantially T-shaped cross section which has a tapered tip 370. Aninternally threaded hole 376 for threadedly receiving an externallythreaded setscrew 374 is defined in an upper surface of the connectingblock 358. The setscrew 374 has a tapered tip 378 which engages in atapered notch 380 defined in the bolt 372. The columnar member 356 hasgrooves 384 of substantially T-shaped cross section which are defined inrespective side surfaces thereof.

The connecting block 358 is mounted on the surface of a cut end of thecolumnar member 356 by inserting the joint pins 368 of the connectingblock 358 into the respective holes 382 in the four corners of thecolumnar member 356 and also inserting the protrusion 364 into thethrough hole 360. Then, the tapered tip 370 of the bolt 372 is heldagainst an inner circumferential surface of a tip end 386 of theprotrusion 364 (see FIG. 40A). The bolt 372 has a head 388 engaging inone of the grooves 384 of another columnar member 356. Thereafter, thesetscrew 374 is threaded into the internally threaded hole 376 in theconnecting block 358 until the tapered tip 378 presses a slanted surfaceof the tapered notch 380, displacing the bolt 372 in the directionindicated by the arrow A. When the bolt 372 is displaced in thedirection indicated by the arrow A, the head 388 of the bolt 372 pullsone of the columnar members 356 to the other columnar member 356 in itsaxial direction, thus joining the columnar members 356 to each other(see FIG. 40B). Since the tapered tip 370 of the bolt 372 spreads thetip end 386 of the protrusion 364 radially outwardly, the teeth366a˜366f on the outer circumferential surface of the tip end 386 biteinto an inner circumferential surface of the through hole 360,preventing the bolt 372 from being pulled out of the through hole 360.In this manner, the columnar members 356 can easily be joined to eachother.

An eighth embodiment of the joint means is shown in FIGS. 41 and 42A,42B.

The eighth embodiment differs from the seventh embodiment in that noteeth 366a˜366f are provided on, but a C-ring 390 is fitted over, theouter circumferential surface of the tip end of the protrusion 364 ofthe connecting block 358, the C-ring 390 having spaced sharp teeth 392on its outer circumferential surface. Because the C-ring 390 with theteeth 392 is mounted on the tip end of the protrusion 364, when thecolumnar members 356 which have been joined are to be separated fromeach other, the bolt 372 is pulled out, allowing the C-ring 390 that hasbeen spread radially outwardly due to elastic deformation to becontracted into its original condition, whereupon the columnar members356 can easily be disconnected from each other. Other structural detailsand joining operation of the joint means according to the eighthembodiment are the same as those of the joint means according to theseventh embodiment, and will not be described in detail below.

A ninth embodiment of the joint means is shown in FIGS. 43 and 44A, 44B.

Each of columnar members 394 in this embodiment has grooves 396 ofsubstantially T-shaped cross section which are defined in outer sidesurfaces, respectively. Each of the grooves 396 has a pair ofconfronting linear grooves 398 defined in its inlet region and extendinglongitudinally of the columnar member 394. Each of the columnar members394 also has a through hole 400 of substantially oblong cross sectiondefined in the bottom of one of the grooves 396 and extendingperpendicularly in communication with a through hole 402 defined axiallyin the columnar member 394. A holder 404 which is inserted in thethrough hole 400 has a first bevel gear 406 integrally disposed on alower portion thereof, an annular groove 410 defined in an upper portionthereof for receiving a C-ring 408 therein, and a substantiallyhexagonal hole 412 defined in an upper end surface thereof. The columnarmember 394 has an internally threaded portion 414 in the vicinity of aninlet of the through hole 402 at the surface of a cut end of thecolumnar member 394, and a bolt 414 is fitted in the through hole 402through the internally threaded portion 414. As shown in FIG. 43, thebolt 416 has a second bevel gear 418 held in mesh with the first bevelgear 406 of the holder 404, an externally threaded portion 420 threadedin the internally threaded portion 414 of the through hole 402, and ahead 422 engaging in one of the grooves 496 of the other columnar member394 to be joined, the second bevel gear 418, the externally threadedportion 420, and the head 422 being integrally formed with each other.

For joining the columnar members 394 to each other, the head 422 of thebolt 416 is placed into one of the grooves 496 in one of the columnarmembers 394, and the bolt 416 is fitted into the through hole 402 in theother columnar member 394. Then, the holder 404 is inserted into theoblong through hole 400 defined in the bottom of one of the grooves 496in the other columnar member 394, and the C-ring 408 fitted in theannular groove 410 of the holder 404 is mounted in the linear grooves398 that are defined in the inlet of the groove 396, so that the holder404 is retained against removal (see FIG. 44A). The holder 404 is thenrotated in a given direction with a hexagonal wrench, for example,inserted into the hole 412 of substantially hexagonal cross sectionwhich is defined in the upper end surface of the holder 404. When theholder 404 is thus rotated, the first bevel gear 406 integral with thelower portion thereof is also rotated, rotating the second bevel gear418 held in mesh with the first bevel gear 406. The rotation of thesecond bevel gear 418 threads the bolt 416 in the direction indicated bythe arrow A, pulling one of the columnar members 394 toward the othercolumnar member 394 in its axial direction (see FIG. 44B). The columnarmembers 394 can therefore easily be joined to each other, and can bejoined to each other reliably with a weaker torque through the first andsecond bevel gears 406, 418 than they are joined with each other throughthe contact between the tip end of the setscrew and the slanted surfaceof the notch in the bolt as with previous embodiments. The joint meansaccording to the ninth embodiment is also advantageous in that anyloosening of the joint between the columnar members 394 due tovibrations or shocks is reduced.

Applications to various pieces of equipment for conveying, machining,and assembling workpieces through the use of a through hole 426 definedcentrally in a columnar member 424 having a cross-sectional shape shownin FIG. 45 will be described below.

In FIG. 46, four grooves 428 are defined in respective inner wallsurfaces of the through hole 426 in the columnar member 424. Aperforated member 430 having ridges that engage in the respectivegrooves 428 is inserted into the through hole 426. The perforated member430 is extrusion-molded of resin, aluminum, magnesium alloy, or thelike, for example, and has a plurality of separate holes 432a˜432ddefined therein. The holes 432a˜432d house wires 434, coaxial andoptical fiber cables 436, an air pipe 438, and liquid pipes 440respectively therein. Therefore, the columnar member 424 is sightly inappearance even if those wires, cables, and pipes are housed therein.The wires, cables, and pipes are prevented from being entangled in theholes 432a˜432d and do not affect other members in the event of aleakage or breakage in the wires, cables, and pipes.

As shown in FIG. 47, the inner wall surface of the through hole 426 maybe coated to use the same as an energy transmission passage 442 fortransmitting microwaves or the like.

As shown in FIG. 48, a ball spline 444 may be employed, and the columnarmember 424 itself may function as a movable body which is relativelymovable through a spline nut 446. The spline nut 446 is installed inplace by inserting pins 448 in grooves defined therein, bringing thepins 448 into engagement with the columnar member 424 for preventing thespline nut 446 from turning with respect the columnar member 424, andthreading a setscrew 450 into the columnar member 424 from an outer sidesurface thereof for retaining the spline nut 446 against removal.

A tenth embodiment of the joint means is shown in FIGS. 49A through 49C.According to the tenth embodiment, a cylinder attachment block caneasily be attached to any of various pieces of equipment for conveying,machining, and assembling workpieces, which are constructed of columnarmembers having grooves of substantially T-shaped cross section.

In FIGS. 49A through 49C, a pneumatic cylinder 456 having a circularrecess 452 defined in a head-side end thereof and internally threadedthrough holes 454 defined in respective four corners thereof hasheretofore been installed on any of various pieces of equipment by abracket, bolts, or the like.

A connecting block 458 is joined to the pneumatic cylinder 456 by bolts461 inserted into through holes 460 defined in respective four cornersof the connecting block 458. When joining the connecting block 458 tothe pneumatic cylinder 456, a circular land 464 on the connecting block458 is inserted into the circular recess 452 in the pneumatic cylinder456, thus positioning the connecting block 458 with respect to thepneumatic cylinder 456. After the connecting block 458 is joined to thepneumatic cylinder 456, a bolt 462 of substantially T-shaped crosssection is inserted into a hole 466 defined in the connecting block 458.The inserted bolt 462 can easily be tightened or loosened by a setscrew468. The pneumatic cylinder 456 and the connecting block 458 are formedby die casting or precision casting, preferably vacuum die casting,vacuum casting, a lost-wax process, extrusion, drawing, metallic powderinjection molding, or ceramic forming.

An eleventh embodiment of the joint means is shown in FIGS. 50A and 50B.According to the eleventh embodiment, columnar members 470, 472 ofdifferent types are joined to each other, and a vacuum ejector system475 with solenoid-operated valves 474 is joined to one of the columnarmembers 472.

FIG. 50B shows a side elevation of the columnar member 472. The columnarmember 472 has attachment through holes 476, fluid passage through holes478, and grooves 480 of substantially T-shaped cross section. Thecolumnar member 472 is joined to the other columnar member 470 through aconnecting block 482 which is sealed by gaskets or the like. Forinstalling the solenoid-operated valves 474 and a pneumatic device suchas the vacuum ejector system 475 on the columnar member 472, which maybe used in any of various pieces of equipment, horizontal air outletholes are defined in outer side surfaces of the columnar member 472. Thevacuum ejector system 475 with the solenoid-operated valves 474 is thenjoined to the columnar member 472. The fluid passage through holes 478are internally threaded at an open end of the columnar member 472, andconnected to pipes for supplying and discharging compressed air. In thismanner, the columnar member 472 may be used in the same manner as amanifold block. The compressed air can be supplied and dischargedthrough the fluid passage through holes 478. The columnar member 472,the solenoid-operated valves 474, and the vacuum ejector system 475 areformed by die casting or precision casting, preferably vacuum diecasting, vacuum casting, a lost-wax process, extrusion, drawing,metallic powder injection molding, or ceramic forming, and mayintegrally formed with each other in certain instances.

In the joint means for use in the actuator structural body, the ends ofcolumnar members, an air balancer, and actuators may be formed into apolygonal cross-sectional shape such as a square or hexagonalcross-sectional shape for thereby increasing the number of sidesurfaces. The ends of the columnar members, the air balancer, and theactuators may also be formed into a circular or substantially circularcross-sectional shape. Desired grooves may be defined in the sidesurfaces, bolts may be loosely fitted in the grooves, and fastened tojoin the columnar members, the air balancer, and the actuators so as toextend in many directions.

The actuator structural member is constructed of the actuators and thecolumnar members that are joined by the joint means. A balancer mountedon one of the actuators which extends substantially vertically forreducing loads on the actuator will be described below.

FIG. 51 is a perspective view of a first embodiment of a balancer housedin a frame with a drive table mounted thereon, FIG. 52 is a frontelevational view of the balancer shown in FIG. 51, with a cover opened,FIG. 53 is a side elevational view, partly in cross section, of thebalancer shown in FIG. 52, and FIGS. 54 through 57 are cross-sectionalviews taken along lines A--A, B--B, C--C, and D--D of FIG. 53.

A balancer 510 according to the first embodiment basically comprises anouter frame 512, a cylinder 514 housed in a recess in the frame 512, atransmitting mechanism 524 having fixed pulleys 520 and drive pulleys522 which transmit extension and contraction of a cylinder rod(hereinafter referred to as a "rod") 516 and are connected to wire ropes518, a drive table 526 linearly displaceable by the transmittingmechanism 524, and a precision pressure-reducing valve 528 connected toa source of compressed air (not shown) for controlling the pressure ofcompressed air supplied to the cylinder 514.

Specifically, the recess in the frame 512 has an opening 530 defined ina side surface of a linearly extending column, and the frame 512 hasgrooves 532 of substantially T-shaped cross section that are defined inother side surfaces thereof than the side surface in which the opening530 is defined. The grooves 532 serve to connect the balancer 510 to anactuator 534 (see FIGS. 60A˜60E) or another balancer through a jointmeans, described later on.

The cylinder 514 housed in the recess in the frame 512 has asingle-acting single rod 516 with members for preventing the drivepulley 522 from turning around the rod 516, a cylinder rod cover 536disposed near the rod 516, and a drive port 538 defined in the vicinityof the cylinder rod cover 536 for supplying compressed air into acylinder chamber (not shown). A cylinder cover 540 is disposed remotelyfrom the rod 516.

The transmitting mechanism 524 for transmitting linear motion of thecylinder 514 has the drive pulleys 522 disposed in a pulley box 542coupled to the distal end of the rod 516, and the fixed pulleys 520operatively connected to the drive pulleys 522 through the wire ropes518 and fixed to the frame 512. As shown in FIG. 55, the rod 516 and thepulley box 542 are held together by a key 544 for preventing them fromturning with respect to each other. The pulley box 542 has guide blocks548a, 548b held against the frame 512 and a lower surface of a guiderail 546, for preventing the pulley box 542 from turning. The guideblocks 548a, 548b are made of a self-lubricating resin such as Duraconor the like, an oleoresin, a self-lubricating soft metal, anoil-impregnated soft metal, a low-friction resin such as Teflon, or alow-friction metal.

The pulley box 542 is preferably extruded of a metal, but may be formedby drawing, metallic injection molding, ceramic injection molding, orplastic injection molding. A cylinder with guides for preventing itselffrom turning, or an elliptical or oblong piston cylinder may be employedfor stabilizing the stroke of the pulley box 542. The pulley box 542 maybe guided directly by a cam follower, a linear bearing, or the like.

The drive pulleys 522 have respective grooves defined in their outercircumferential surfaces for receiving the wire ropes 518, and arecovered with a hood 552 of the pulley box 542. The hood 552 serves toprevent the wire ropes 518 from being dislodged from the grooves 550 ofthe drive pulleys 52. A pulley box 554 with the fixed pulleys 520 housedtherein is fixedly positioned at an end of the stroke of the drivepulleys 522. The fixed pulleys 520 housed in the pulley box 554 haverespective grooves 550 for receiving the wire ropes 518, and the pulleybox 554 has a hood 552 for preventing the ropes 518 from being dislodgedfrom the grooves 550.

The pulley box 554, to which ends of the wire ropes 518 are fixed, hasholes 556 defined therein for adjusting the stroke of the drive pulleys522. The pulley box 554, the cylinder rod cover 536, and the cylindercover 540 are fixed to the guide rail 546 for the drive table 526, andare rendered integral with the cylinder 514 and the pulley box 542through the guide rail 546.

The drive table 526 is mounted on the guide rail 546 and has a groove560 and a holder 561 for securing the wire ropes 518. If the balancer510 is connected to the actuator 534, then the drive table 526 is joinedto a table of the actuator 534 by a joint table 562 (see FIGS. 60A˜60E).If the balancer 510 is used as being separate from the actuator 534 orused singly by itself, then the balancer 510 may directly carry aworkpiece. The drive table 526 is formed of the same material in thesame manner as the drive pulley box 542.

The balancer 510 according to this embodiment has the drive table 526,the guide rail 546, and the frame 512, which are highly rigid, in orderto reinforce the body rigidity and the moment-resistant rigidity of theguide rail at the time the actuator 534 is moved over a vertical stroke,and also to allow the balancer 510 to be used singly.

However, if it is not necessary to avoid a reduction in the service lifecaused by insufficient parallelism between a guide rail of the actuator534 and the guide rail 546 of the balancer 510 when they are installed,or to avoid insufficient rigidity at the time the actuator 534 is movedover a vertical stroke, or if it is not necessary to use the balancer510 singly, or if drive units of the actuator 534 and the balancer 510integrally on the common frame 512 (see a third embodiment describedbelow), then the drive table 526, the guide rail 546, and the frame 512,which are highly rigid are not required. In such a case, the drive table526 is connected to an actuator cable or a workpiece by a flexible jointonly through vertical positioning for preventing the guide rail of theactuator 534 from being shortened in service life.

Alternatively, it is possible to guide the drive table 526 for movementover its stroke with a linear slide bearing, a cam follower, or the likeas with the drive pulley box 542 for thereby intentionally lowering therigidity to maintain a desired service life, reduce the weight, andlower the cost.

The drive table 526 may be dispensed with, and the wire ropes 518 may befixed directly to the actuator 534 or a workpiece, so that the balancer510 can greatly be reduced in weight and cost.

An end block 566 with a cushion 564 is disposed on an end of the guiderail 546 for the drive table 526 for preventing a workpiece from beingdislodged due to the lack of a vertical resistive load which resultsfrom a failure such as a breakage of the wire ropes 518, the stoppage ofair supplied to the cylinder 514, or the like.

The cushion 564 is made of urethane. However, a shock resistant orabsorbing resin, a spring, a shock absorber, or the like may be used asthe cushion 564 depending on a vertical load applied thereto.

To the end block 566, there are attached a drive unit cover 568 andpneumatic pressure regulator covers 570 of the balancer 510.

Drive forces produced by the cylinder 514 are transmitted to the drivetable 526 by the wire ropes 518. At this time, a stroke which is twicethe stroke of the cylinder 514 is imparted to the drive table 526 by thedrive pulleys 522 and the fixed pulleys 520.

Therefore, the stroke of the cylinder 514 may be about one half of thestroke of the balancer 510. As a consequence, the balancer 510 can bereduced in size, and it is not necessary for the balancer 510 to have aprojected portion when it operates over its stroke. The stroke of thecylinder 514, which is one half of the stroke of the balancer 510,allows the internal pressure of the cylinder 514 to change to a smallerdegree when the cylinder 514 operates over its stroke. This is highlyadvantageous for the control of the internal pressure of the cylinder514.

On the other hand, the output power of the cylinder 514 is twice theoutput power of the balancer 510. However, if the pneumatic pressuresupplied to the cylinder 514 is increased to produce an increased outputpower, then the speed of flow of air can be increased under the highpneumatic pressure, which is advantageous for the control of theinternal pressure of the cylinder 514.

The wire ropes 518 have externally threaded terminals 572 on theiropposite ends which extend through the two fixing holes 556 in the fixedpulley box 554 and are fixed in position by nuts 574. The wire ropes 518have intermediate portions placed in the fixing groove 560 in the drivetable 524 and secured by the holder 561.

The stroke of the drive table 526 is adjusted by using wire ropes 518having different lengths. The stroke of the drive table 526 can befinely adjusted by the externally threaded terminals 572 and the nuts574. Alternatively, an adjusting mechanism for adjusting the stroke ofthe drive table 526 may be mounted on the drive table 526. Inasmuch asthe wire ropes 518 have a relatively small cross-sectional area withrespect to tensile loads imposed thereon and can be bentthree-dimensionally, the pulleys can be desired and positioned with highfreedom, making it possible to reduce the size of the double-speedmechanism.

The wire ropes 518 are in the form of twisted wires of stainless steelwhich are coated with polyurethane, Teflon, nylon, or the like that isimpregnated with wear resistant oil. However, the wire ropes 518 maycomprise twisted wires of tungsten, fibers of polyimide, twisted wiresof amorphous metal, twisted wires of resin, twisted wires of a compositematerial, or the like.

If the wire ropes 518 are only required to be bent two-dimensionally,then they may be replaced with belts of amorphous metal, wire belts,chains, rubber belts, or the like. With the balancer 510 according tothis embodiment, a vertical load is applied to the right as shown,subjecting the rod 516 to a tensile load at all times. Accordingly, therod 516 is prevented from being buckled even when it is moved over alarge stroke. Drive forces which are resistant to the vertical load aregenerated under the internal pressure of the cylinder 514, and have tobe controlled at a constant level at all times.

The balancer 510 has the precision pressure-reducing valve 528 foradjusting the pneumatic pressure in the cylinder 514. The internalpressure of the cylinder 514 can be set to a desired level depending onthe vertical load by an adjustment screw 576 of the precisionpressure-reducing valve 528. The internal pressure of the cylinder 514can be confirmed by a pressure gage 578. The drive port 538 of thecylinder 514 is connected to an output port 580 of the precisionpressure-reducing valve 528. When the volume of the cylinder chamber inthe cylinder 514 increases as the balancer 510 operates over its strokeand the internal pressure of the cylinder 514 drops below a presetpressure, the precision pressure-reducing valve 528 operates to supplycompressed air from a compressed air supply port 582 quickly into thecylinder 514. When the volume of the cylinder chamber decreases and theinternal pressure of the cylinder 514 rises above the preset pressure,compressed air in the cylinder 514 is discharged from a discharge port584 into the atmosphere.

The precision pressure-reducing valve 528 may be replaced with aservovalve such as an electropneumatic proportional valve, a controller,and a sensor (not shown). In such a case, drive forces may beestablished and adjusted by a drive force sensor, or may automaticallybe controlled in a mode of setting a resistive load by a vertical loadsensor. Alternatively, the internal pressure of the cylinder 514 may becontrolled depending on a motor position or a motor load throughcommunications with a motor controller (not shown) for the actuator 534.

Rather than controlling the internal pressure of the cylinder 514 at aconstant level, the drive forces may intentionally be increased orreduced in the direction to drive the actuator 534 for thereby bearingnot only the vertical load but also drive forces due to the verticalacceleration. The balancer 510 thus arranged is rendered more active,resulting in a pneumatic-electric composite system which is composed ofthe cylinder 514 and a motor.

The balancer drive unit and the precision pressure-reducing valve 528which are integrally combined with each other by the guide rail 546 arefastened by screws or the like to a plate 588 that is inserted in arail-like groove 586 defined in the inner bottom of the frame 512. Asshown in FIG. 58, the rail-like groove 536 has a clearance 589 forpermitting the plate 588 to be inserted obliquely from the opening 530in the frame 512. This arrangement allows structures on the plate 588 tobe freely disposed, together with the plate 588, longitudinally in theframe 512. The clearance 589 is useful not only for adjusting the strokeof the balancer 510, but also for fixing the plate 588 at any desiredposition in the frame 512 which has a sufficient length or placing aplurality of plates at any desired positions in the frame 512.

The frame 512 has the grooves 532 or T slots defined in opposite outerside surfaces and an outer bottom surface, and can easily be installedby T bolts (described later on) to an attachment surface withoutlimitations thereon. The frame 512 is made by extrusion, drawing,metallic injection molding, ceramic injection molding, or the like. Endblocks 594 are fastened to opposite ends, respectively, of the frame 512by screws threaded into cylindrical grooves 590 and holes 592.

As shown in FIG. 59, the balancer 510 can be joined to a frame 512 ofthe actuator 534 which is of the same shape as the frame 512 of thebalancer 510 and has grooves 532 of substantially T-shaped cross sectionthat are defined in an outer side surface thereof. Each of the endblocks 594 of the balancer 510 has two horizontal holes 591 for T bolts593. The T bolts 593 have larger-diameter portions 595 fittedrespectively in larger-diameter holes 597 defined in the end block 594.When nuts 599 with hexagonal holes which are inserted from holes remotefrom the larger-diameter holes 597 are threaded over the T bolts 593,the T bolts 593 join the balancer 510 and the actuator 534 to eachother.

The larger-diameter holes 597 defined in the end block 594 aresymmetrical with respect to a central axis of the end block 594.Therefore, the balancer 510 can be attached to either one of oppositeside surfaces of the actuator 534. Attaching the actuator 534 and thebalancer 510 to each other through the grooves 532 of substantiallyT-shaped cross section in the direction of their stroke requires thestroke of the actuator 534 and the balancer 510 to be adjusted.

FIGS. 60A through 60E show pneumatic double-speed balancers of compactconfiguration according to the present embodiment which are joined tovarious actuators by the process of variously and easily adjusting thestroke and the simple means for attaching them with the grooves 532 ofsubstantially T-shaped cross section, the pneumatic double-speedbalancers being capable of bearing vertical loads and imparting highframe and guide rigidity.

Based on the above features, the number of balancers 510 joined to theactuator 534 can be increased or reduced to largely adjust the abilityto bear the vertical load. The balancer 510 may be used singly becauseof its high frame rigidity, guiding capability, and installability, ormay be spaced from the actuator 534 in an arrangement depending on theload to be borne.

FIG. 61 shows a second embodiment of the balancer. Those components inthis and following embodiments which are identical to those of thebalancer according to the first embodiment are denoted by identicalreference numerals, and will not be described in detail below. In adouble-speed mechanism which employs pulleys, wire ropes 518 may bedislocated from the pulleys when they are slackened or subjected to aload in a direction opposite to the vertical load or not subjected toany load. According to the first embodiment, the wire ropes 518 areprevented from being dismounted from the pulleys by the hoods 552covering the fixed pulleys 520 and the drive pulleys 522.

According to the second embodiment, a balancer 600 is of such astructure as to give tension to wire ropes 604 at all times irrespectiveof the position of a drive table 602 and the load condition, for therebypreventing the wire ropes 604 from being dislocated. A drive pulley box606 has first and second drive pulleys 608, 610.

The balancer 600 includes a cylinder 612 having a head cover 614 servingas a second fixed pulley box which houses second fixed pulleys 613 andhas second wire rope fixing holes 615.

The wire ropes 604 have ends fixedly mounted in first wire rope fixingholes 616, are trained around the first drive pulleys 608 and firstfixed pulleys 618, and are fixed to a wire fixing block 620 of the drivetable 602. The wire ropes 604 are also trained around the second fixedpulleys 613 and the second drive pulleys 610, and have opposite endsfixedly mounted in the second wire rope fixing holes 615.

The balancer 600 according to the second embodiment, which is of theabove structure, operates as follows:

A vertical load is applied in the direction indicated by the arrow A inFIG. 61. Drive forces produced when the cylinder 612 pulls its cylinderrod are transmitted by the wire ropes 604 through the first drivepulleys 608 and first fixed pulleys 618 to the drive table 602 to movethe drive table 602 over a stroke which is twice the stroke of thecylinder 612, as with the first embodiment.

At this time, the second drive pulleys 610 move toward the second fixedpulleys 613, causing the wire ropes 604 to extend by a length which istwice the stroke of the cylinder 612, i.e., which is equal to thedistance that the drive table 602 moves, from the drive table 602 to thesecond fixed pulleys 613.

When the drive table 602 is moved in a direction opposite to thevertical load while no drive forces are being produced by the cylinder612, the wire ropes 604 from the drive table 602 transmit forces throughthe second fixed pulleys 613 to the second drive pulleys 610 which movethe drive pulley box 606 in the direction indicated by the arrow B. Thefirst drive pulleys 608 now take up the wire ropes 604 by a length equalto the distance that the drive table 602 moves, from the drive table 602to the first fixed pulleys 618.

Consequently, the wire ropes 604 are kept under tension at all timesregardless of the load and the position of the drive table 602.

The stroke of the drive table 602 can greatly be varied with ease byvarying the position in which the wire ropes 604 are fixed to the drivetable 602.

If the ports of the cylinder 612 are modified to convert the cylinder612 to the rod-pushing type, then the cylinder 612 can generate driveforces in the opposite direction, making it possible to use the balancer600 upside down. This allows a precision pressure-reducing valve 622 anda stroke to be freely selected.

If the cylinder 612 is of the double-acting type, then it may be used asa rodless cylinder having a horizontal stroke, which may be incorporatedin a pneumatic-electric composite drive system which is composed of aservovalve, a controller, and an electric actuator as shown in the firstembodiment, for pneumatically moving a workpiece and electricallypositioning the workpiece.

In such a case, the workpiece which is being moved may be decelerated bymagnetic braking with a motor (not shown). The wire ropes of thedouble-speed mechanism may also be prevented from being dislocated fromthe pulleys by spring forces which cause the cylinder 612 to generatesufficient drive forces in a direction to tension the wire ropes 604 atall times. In FIG. 61, for example, a spring may be contained in thecylinder 612 to apply drive forces in a direction to contract therodless cylinder for imparting rightward forces to the drive pulley box606 at all times thereby to prevent the wire ropes 604 from beingdislodged due to slackening. Alternatively, tensioners for tensioningthe ropes or belts may be provided.

Since the vertical resistant load is borne by only the ropes or belts,an automatic brake system or the like is needed particularly when thebalancer is subjected to heavy loads, for safety precautions in theevent of a breakage of the ropes or belts.

A third embodiment in which a balancer and a balancer drive unit areintegrally disposed in a common frame is shown in FIG. 62.

In FIG. 62, the inner bottom surface of an opening defined in anintegral common frame 630 has two substantially parallel grooves 586 forinserting plates 588 on which drive units of an actuator 534 and abalancer 510 are fixedly mounted. The drive units are fixedly disposedin the frame 630 through the plates 588. The frame 630 has grooves 532of substantially T-shaped cross section which are defined in outer sidesurfaces thereof.

The balancer 510 has a pulley box 542 fixed to distal ends of rods 632a,632b, 632c of cylinders with guides (not shown). The pulley box 542 isprevented from being turned by a mechanism (not shown). The balancer 510has a drive table 634 shared by the actuator 534. Wire ropes 518 areaffixed to the actuator drive table 634. A workpiece is verticallyguided by a guide rail 636 of the actuator 534. Therefore, the guiderail 636 should preferably be of high rigidity.

According to this embodiment, the drive table 634 of the balancer 510,the guide rail 636, and the frame 630 are shared by the actuator 534,resulting a greatly reduced weight and cost. With the actuator 534 andthe balancer 510 disposed in the common frame 630, the balancer 510 maybe small in size with respect to the entire length of the actuator 534.

Arrangements in which actuators and the balancer 510 according to thefirst embodiment are juxtaposed are shown in FIGS. 63 through 68.

FIGS. 63, 65, and 67 are front elevational views of balancers 510 andrespective actuators 638, 640, 642 that are juxtaposed, with coversopened. FIGS. 64, 66, and 68 are transverse cross-sectional views of thearrangements shown in FIGS. 63, 65, and 67, respectively.

The actuator 638 shown in FIG. 63 has a frame 512 which is substantiallyidentical to a frame 512 of the balancer 510. A timing belt 650 trainedaround a motor pulley unit 646 and an idle pulley unit 648 disposed in arecess defined in the frame 512 is rotated by a motor 644 which is alsodisposed in the recess. Upon rotation of the timing belt 650, a table652 supported by the timing belt 650 is linearly displaced, and anelongate joint table 562 that is joined to the table 652 and a drivetable 526 of the balancer 510 is linearly displaced in a substantiallyvertical direction. In response to energization of the motor 644,therefore, the actuator 638 displaces the joint table 562 in asubstantially vertical direction for moving a workpiece, for example,substantially vertically. The balancer 510 serves to reduce a load onthe motor 644 of the actuator 638.

The actuator 640 shown in FIG. 65 has a frame 654 having grooves 532 ofsubstantially T-shaped cross section defined in outer side surfacesthereof, which are similar to those of a frame 512 of the balancer 510,the frame 654 being wider than the frame 512. The frame 654 has a recesshousing therein a motor pulley unit 656, a table 658, and an idle pulleyunit 660. The motor pulley unit 656 has a pulley 662 which can berotated by a bevel gear 666 coaxially connected to the pulley 662 andheld in mesh with a bevel gear 668 that is coupled to the drive shaft ofthe motor 664. When the pulley 662 is rotated, a table 672 supported bya timing belt 670 is linearly moved. The table 672 supported by thetiming belt 670 is slidably displaceable. Other structural details andoperation of the actuator and the balancer shown in FIGS. 65 and 66 arethe same as those of the actuator and the balancer shown in FIGS. 63 and64, and will not be described in detail below.

The actuator 642 shown in FIG. 67 has a frame 676 which is as wide asthe frame 654 shown in FIG. 65. The frame 676 has a recess housingtherein a first housing 680 which supports one end of a ball screw 678,a second housing 682 which supports the opposite end of the ball screw678, a table 684 having a through hole in which the ball screw 678extends and linear displaceable along the ball screw 678, and a timingbelt 692 trained around a pulley 686 coupled to the end of the ballscrew 678 near the second housing 682 and a pulley 690 coupled to thedrive shaft of a motor 688. When the motor 688 is energized, the pulley690 rotates the timing belt 692, which then rotates the pulley 686thereby to rotate the ball screw 678 coaxial with the pulley 686 fordisplacing the table 684.

The actuator 642 is useful for installation in a limited space. To makethe actuator 642 thus useful, the ball screw 678 is positioned closelyto an end of the frame 676, and the drive shaft of the motor 688 ispositioned laterally of the axis of the ball screw 678. Therefore, ifthe actuator 642 is to be placed in a space with horizontal dimensionallimitations, then the ball screw 678 and the drive shaft of the motor688 may be longitudinally aligned with each other. Accordingly, theactuator 642 can be arranged for use in spaces with dimensionallimitations in various directions.

Various assemblies of the actuator structural body with a plurality ofactuators and an air balancer being arranged for conveying workpieceshave been described above. However, the present invention is not limitedto the above assemblies. Columnar members and actuators may be combinedin various ways to produce actuator structural bodies for conveyingworkpieces in vertical and horizontal directions. Examples of suchactuator structural bodies will be described below.

Conveyor devices and an assembling working table which are constructedof structural members and connecting blocks are shown in FIGS. 69 and70.

As shown in FIG. 69, a conveyor device 716 constructed of connectingblocks 714 has a plurality of structural members 718, 719 that make up aframework substantially in the form of a rectangular parallelepiped, adrive motor 720 coupled to an end of one of substantially parallelstructural members 718 that are elongate, and a plurality of rotatablerollers 724 which can be rotated by the drive motor 720 through a timingbelt 722. Shaft motors may be used which comprise the rotatable rollers724 each incorporating the drive motor 720. The conveyor device 716 isassociated with reinforcing members 726 which increase equipmentrigidity in regions where loads are applied.

When the conveyor device 716 which has been constructed is modified orexpanded, the conveyor device 716 does not need to be disassembled, butother structural members or devices may be joined to the conveyor device716. In FIG. 69, a working table 732 can easily be added to the conveyordevice 716 simply by joining a structural member 730 through grooves 728of substantially T-shaped cross section which are defined in outer sidesurfaces of structural members 719.

As shown in FIG. 70, an actuator 736 and a conveying table 738 arejoined to the conveyor device 716 through structural members 734, and acylinder 742 with two rods is joined to a movable body 740 of theactuator 736, the cylinder 742 supporting an air chuck 744 mounted onthe distal ends of the rods thereof. While a workpiece (not shown)conveyed by the conveying table 738 is being gripped by the air chuck744, the actuator 736 is operated to move the cylinder 742 coupled tothe movable body 740 toward the conveyor device 712 for therebyconveying the workpiece.

Assemblies of a plurality of structural members and actuators coupledthereto are shown in FIGS. 71 through 73. In FIGS. 71 through 73,identical components are denoted by identical reference numerals, andwill not be described in detail.

A first assembly 745 shown in FIG. 71 comprises a plurality ofstructural members 746, 747, 748, 749 which make up a skeleton, firstthrough third actuators 750, 751, 752, a working table 754, a workpiece756, a workpiece holder plate 758 and a workpiece storage box 759,movable bodies 760, 761, 762, a first cylinder 766 with a suction pad764 being coupled as a workpiece gripping means, and a second cylinder768 with a cylinder rod being projected.

The first actuator 750 serves to linearly move the second actuator 751mounted on an upper surface of the movable body 760 associated with thefirst actuator 750. The first cylinder 766 with the suction pad 764being coupled thereto is joined to the movable body 761 which isassociated with the second actuator 751 which is connectedperpendicularly to the first actuator 750. The second cylinder 768 isjoined to the movable body 762 which is associated with the thirdactuator 752, for positioning the workpiece 756. A motor box 770 isdisposed at a junction between the first actuator 750 and the structuralmember 748, and a valve unit 772 is disposed at a junction between thethird actuator 752 and the structural member 748.

The first assembly 745 operates as follows: Compressed air is suppliedthrough fluid passages in the structural members to the first cylinder766 coupled to the second actuator 751. When the compressed air issupplied, the cylinder rod of the first cylinder 766 is displaceddownwardly, and the suction pad 764 attracts the workpiece 756 which ispositioned in the workpiece storage box 759. Compressed air is suppliedagain to displace the cylinder rod upwardly, and while the cylinder rodis being displaced upwardly, the movable body 760 of the first actuator750 is moved upwardly, thereby moving the second actuator 751 coupled tothe movable body 760 of the first actuator 750. The second actuator 751stops moving when the workpiece 756 attracted by the suction pad 764 hasmoved near a position above a desired position. The movable body 761 ofthe second actuator 751 is moved horizontally, and the cylinder rod ofthe first cylinder 766 is lowered to insert the workpiece 756 into adesired hole 774 defined in the workpiece holder plate 220. The cylinderrod of the third actuator 752 is displaced to position the workpiece.

FIGS. 72 and 73 show second and third assemblies 776, 778, respectively.In each of the second and third assemblies 776, 778, sequencers 782, 784with programming boards, which function as actuator controllers, aremounted on a structural member 780. In FIG. 73, a mechanical hand 786 isconnected to the distal end of a first cylinder 766. The sequencers 782,784 with programming boards are detachably mounted on the structuralmember 780. A belt conveyor actuator 790 combined with endless belts788, 789 is positioned closely to the sequencers 782, 784 withprogramming boards. A plate 792 can be conveyed by the belt conveyoractuator 790.

In FIGS. 72 and 73, various signals such as electric signals, fluidpressure signals, or the like to be supplied to the sequencers 782, 784with programming boards are transmitted through inner passages (notshown) defined in the structural members and actuators, as describedabove.

FIG. 74 shows a second assembly of the actuator structural body which issimilar to the assembly shown in FIG. 20. Those components of the secondassembly which are identical to those of the assembly shown in FIG. 20are denoted by identical reference numerals, and will not be describedin detail below.

An actuator structural body 800 shown in FIG. 74 basically comprises afirst section 802 and a second section 804 disposed parallel to thefirst section 802, with a belt conveyor 806 being disposed parallel tothe second section 804. The first section 802 and the second section 804are selectively used depending on a working process to be effected on aworkpiece.

The first section 802 comprises a motor box 810 and a controller 812having a display unit, the motor box 810 and the controller 812 beingpositioned on one end of an actuator 808 and lying flush with an uppersurface of the actuator 808. Since the motor box 810 and the controller812 lie flush with the upper surface of the actuator 808, they providecompatibility when they are mounted on another member. Because the motorbox 810 and the controller 812 are compact in shape, they caneffectively utilize a space. Other motor boxes 242, etc. shown in FIG.74 may also be disposed flush with upper surfaces of actuators 210.

The second section 804 comprise balancers 818, 820 associated withrespective actuators 814, 816 and extending vertically in confrontingrelationship to each other. Opposite ends of an actuator 822 are joinedto respective movable bodies of the actuators 814, 816 and the balancers818, 820. The actuator 822 extends substantially perpendicularly to theactuators 814, 816 and the balancers 818, 820, and is joinedsubstantially horizontally. The actuator 822 has a movable body 824 towhich an actuator 208 is joined, and the actuator 208 has a movable body226 to which there is joined a cylinder 828 with a mechanical hand 826connected to the distal end of a rod thereof. Actuators 210 are joinedlongitudinally to each other at a junction between the first and secondsections 802, 804. The actuators 210 have respective movable bodies 228to which there are joined respective cylinders 236 having respectivepositioning cylinder rods 234.

The belt conveyor 806 is coupled to the first section 802, andprogramming keyboards 830, 832, each functioning as an input/outputdevice for a control system, are disposed at a junction between the beltconveyor 806 and the first section 802. The programming keyboards 830,832 are detachably mounted on a columnar member 202, and allow thecontrol system (described later on) to manage various devicesincorporated in the actuator structural body 800, i.e., the actuators210, 206, 208, 808, 814, 816, the balancers 212, 818, 820, the cylinders232, 236, 838, the mechanical hand 826, and the belt conveyor 806. Thecontrol system comprise various controllers, processors, circuits fortransmitting various signals including optical signals, electricsignals, fluid pressure signals, etc., and circuits for transmitting andreceiving radio signals, which are housed in the actuators 210, 206,208, 808, 814, 816 and the columnar member 202.

FIG. 75 shows the actuator structural body in which the actuator 208 ofthe first section 802 is replaced with another actuator 834. Thereference numeral 836 represents a movable body.

An application in which the actuator structural body 800 functions as anindependent production line having a plurality of processing steps willbe described below.

As shown in FIG. 76, a parts pallet 841 having an ID module (not shown)is conveyed from a warehouse 838 by an unmanned vehicle 840 along a beltconveyor 806. The parts pallet 841 enters the first section 802 of theactuator structural body 800 where it is processed. Each of workpieces216 also has an ID module. Thereafter, the parts pallet 841 is deliveredto the second section 804 by a conveying means (not shown). In thesecond section 804, the parts pallet 841 is processed. After being fullyprocessed by the production line, the parts pallet 841 is delivered toanother process.

An application in which each of the sections 802, 804 of the actuatorstructural body 800 functions as an independent production line will bedescribed below.

In FIGS. 74 and 76, the actuator 808 is controlled by an actuatorcontroller 1, the actuator 208, the cylinder 232, and the suction pad230 by an actuator controller 2, and the actuator 206 and the balancer212 by a balancer controller 1. The actuator controllers 1, 2 and thebalancer controller 1 are connected to a multiaxis controller 1 througha multibus 842 and controlled as one working unit thereby. The actuator210 and the cylinder 236 are coordinately controlled by an actuatorcontroller 3. The actuator 210 and the cylinder 236 are connected to amultiaxis controller 2 through a multibus 844 and coordinatelycontrolled as one working unit thereby.

Coordinated control of the first section 802 of the actuator structuralbody 800 is carried out by a supervisory microprocessor 1 which isconnected to the multiaxis controllers 1, 2 by a LAN which employselectric signals, optical signals, radio communications, etc.

In the second first section 804 of the actuator structural body 800, theactuator 822 is controlled by an actuator controller 4, the actuator208, the cylinder 828, and the mechanical hand 826 by an actuatorcontroller 5, the actuator 210 and the cylinder 236 by an actuatorcontroller 6, the actuator 814 and the balancer 818 by a balancercontroller 2, and the actuator 816 and the balancer 820 by a balancercontroller 3. The balancer controllers 2, 3 are connected to a localcontroller 846 for moving the actuator 822 substantially verticallywhile keeping it horizontal, and controlled for coordinatedsynchronization. The actuator controllers 4, 5 and the local controller846 are connected to a multiaxis controller 3 through a multibus 848 andcoordinately controlled as one working unit thereby. Therefore,coordinated control of the second section 804 is also carried out by asupervisory microprocessor 2 which is connected to the multiaxiscontrollers 3, 4 by a LAN which employs on electric signals, opticalsignals, radio communications, etc. The actuator controllers 1˜6 canfunction as balancer controllers, respectively, and the balancercontrollers 1˜3 can function as actuator controllers, respectively.

The belt conveyor 806 is controlled by a belt conveyor controller 850,and the unmanned vehicle 840 and the warehouse 838 are controlled by acontrol device, a control system, or the like which are not shown.

Respective control devices (not shown) of the supervisorymicroprocessors 1, 2, the belt conveyor controller 850, the unmannedvehicle 840, and the warehouse 838 are connected in a network comprisinga LAN which employs on electric signals, optical signals, radiocommunications, etc., and can freely transfer information therebetween,thereby making up a coordinated control system for the actuatorstructural body 800 as an independent production line.

The above control system depends on a certain host computer for overallcoordinated control, and provides a centralized control system forcontrolling the control devices through its nodes. The centralizedcontrol system has many advantages, but is disadvantageous in that theentire network will go down if the host computer goes down, and changesand additions of nodes and control devices need a large-scalemodification of the control application program. In view of the abovedrawbacks, the control devices and control units of the control systemmay have self-controlling application programs and operate while inmutual communications, making up a decentralized intelligent controlsystem based on a LON (Local Operating Network) which requires no hostcomputer. In the decentralized intelligent control system, the controlapplication programs dispersed in the respective nodes have a simplestructure and can flexibly cope with additions and changes of thenetwork and the node control devices (see Japanese patent publicationsNos. 3-504066 and 3-505642).

To the LAN, there are connected not only the control system for theactuator structural body 800 as an independent production line, but alsoother production, supervisory, information, communication, and controlsystems, thus making up a larger-scale coordinated productionsupervising system. For example, a production supervising computer 852which operates as a host management computer as in FA, CIM may beconnected to the LAN, so that the LAN may be part of a larger-scalecoordinated production supervising system network. In such a case,procedures for placing orders, managing processes, assembling,machining, and conveying workpieces, and program procedures or programediting for operating controlled objects including actuators, sensors,pallets, robots, control devices, etc. are carried out depending on theprocesses and an ordering system which are supervised by CIM.

An input/output device 854 such as the programming keyboards 830, 834shown in FIG. 74 is provided as a user interface for the above system.The input/output device 854 may freely be connected to controllers,processors, computers, etc. through general-purpose interfaces such asRS232C, RS422C, etc., a LAN which employs electric signals, opticalsignals, radio communications, etc., a multibus, an Ethernet, or a tokenring. An input/output device 856 or a general-purpose interface isprovided which can be connected to a host CIM computer, controllers,processors, etc. In such a case, a control program can be edited,generated, modified, downloaded, uploaded, inputted and outputted by notonly the host CIM computer, but also each of the controllers,processors, computers, etc., and each of the controllers, processors,computers, etc. can be accessed. All the each of the controllers,processors, and computers may be directly connected to each other by anetwork, or may be directly connected to each other by a virtual networkthrough a software approach. This makes it possible to control theoverall working site, monitor and manipulate supervisory information, toincrease the working efficiency, and to individually control eachoperation and step while maintaining the coordinated nature of theentire system. The entire system is thus made highly flexible, resultingin a configuration highly effective for system modifications andmaintenance and production of many product types in small quantities.

The controllers, processors, and computers may communicate with eachother through the multibus and the LAN, but may be directly connected toeach other by a network or a virtual network through a softwareapproach. Furthermore, they may be integrated by the OS of a hostcomputer, a slave computer, a PC, a local controller, a UNIX, aminicomputer, or a microcomputer, or an object architecture based on thewindow of a splashboard of the Macintosh OS. The CAD/CAM/CAE/LA datastructure of a graphic/two-dimensional/solid modeling program, e.g.,Ideas of SDRC Inc., CADAM or DB2 of IBM Inc., CAE of CATIA Inc., a DXFof AUTOCAD In., or the like, may be used to simulate a design ordevelopment process as a concurrent engineering process. In this case,it is effective to utilize the technology of virtual reality as aman-machine interface (MMI).

The user interface of the system may comprise be implemented by virtualreality as disclosed in Japanese patent application No. 5-36901. In sucha case, an existing production system, network, parts, or orderingstatus may be presented in a virtual space as assistance for systemrecognition. Moreover, a virtual reality recognition system depending ona user (a system builder, a programmer, a production planner, amaintenance person, or the like) may be provided to assist in operationand understanding, irrespective of the actual factory equipment, and thestructure and arrangement of the FA system. In this manner, recognizedsystem and the actually constructed system can be separated, and theactually constructed system does not need to depend on the ability ofthe user. This allows a single actually constructed system to berecognized and operated as a plurality of simultaneous virtual realityrecognition systems, allows an actually constructed system to bemodified without hardware modifications by modifying a virtual realityrecognition system, allows an actually constructed system to be dividedon the time domain and operated (time sharing), or allows an actuallyconstructed system to be divided on the space domain and operated(multilayering), so that the system can be operated beyond the limits ofthe user with respect to space and time recognition. This systemcomprises a system (GOD) for coordinately supervising and controllingthe actually constructed system and a system (DEVIL) for translating theactually constructed system into a virtual reality recognition systemand presenting the virtual reality recognition system to the user.

In the production system of the actuator structural body 800 that isstandardized under the CIM supervision, the standardized structural body800 with the workpiece 216 as its component, the actuators 210, 206,208, 808, 814, 816, the suction pad 230, the mechanical hand 826, andthe cylinders 232, 236, 828 may be replaced with an artificial-life CIM(ALCM) system which generates and maintains its production system byitself. Alternatively, the system may be propagated itself from aminimum ALCIM system or a production line into an overall factoryproduction system or a regional group-factory production system. It willbe possible for the system to be constructed as a biological systemowing to advances in genetic technology in the future. In this case, thesystem may be propagated itself from a single super-DNA/RNA seed to aproduction system or a factory. A fully self-propagated artificial-lifemanufacturing system (ALMS) is highly effective in various applications,e.g., factories, mass-handling systems, medical fields, homes, specialenvironments such as atomic energy and vacuum environments, orsuperclean rooms, and regions of severe environments for survival, suchas polar regions, rigorously cold regions, deep sea, space, or planets.It is possible to provide ALMSs having a plurality of productionpurposes in a limited single environment, and integrate their systemscales, abilities, and efficiencies into a composite ALMS which isoptimum for demand capabilities and environmental conditions in thesingle environment. The composite ALMS may continuously be givenself-propagating, self-modifying, and mutating abilities for growing acomposite ALMS for use in a single environment which can maximally adaptitself to demand capabilities and environmental conditions that vary atall times. The above optimization concept based on a combination ofsystems is effective for use in a self-modifying system such as AIsystem, and is effective to optimize not only the ALMS but also systemsupervising software, network priority, manufacturing line construction,manufacturing priority, process division and construction, etc. Theabove optimization concept based on a combination of systems alsosuggests a possibility of operation of a CIM system based on acombination of systems which have independent controlling capabilities.The CIM system does not have a specific centralized control system, andis coordinately operated in its entirety by the consensus of all theindependent control systems of the overall CIM system. The consensus maybe formed under the supervision of a certain one of the independentcontrol systems. Alternatively, certain parts of all the independentcontrol systems which are of decentralized hardware and make up theentire system may be linked and function in an coordinated manner. Ifthe consensus is reached in view of the importance of requests and tasksof the respective independent control systems, then it is possible tocontrol the entire system optimally at all times.

We claim:
 1. An actuator structural body for moving a workpiece,comprising:a plurality of columnar bodies, wherein one of said columnarbodies comprises an actuator having T-shaped grooves defined alongrespective outer side surfaces thereof; another of said columnar bodiescomprising a columnar member having a plurality of T-shaped groovesdefined along respective outer side surfaces thereof, and furthercomprising a through hole defined inside said columnar member; and jointmeans for joining said actuator and said columnar member together byfitting a head portion of said joint means within at least one of theT-shaped grooves of said actuator and securing another end of said jointmeans inside said through hole of said columnar member.
 2. An actuatorstructural body according to claim 1, wherein said actuator comprises arecess defined in one of said outer side surfaces of said one of saidcolumnar bodies, further comprising:a drive source housed in said recessand comprising a first induction motor as a main motor and a secondinduction motor as an auxiliary motor for assisting or controlling saidmain motor; power transmitting means for transmitting drive power fromsaid drive source to a movable body; displacement detecting means fordetecting a displacement of said movable body; and control means forcontrolling drive power from each of said main motor and said auxiliarymotor based on the displacement detected by said displacement detectingmeans, thereby to control a position to which or a speed at which saidmovable body is moved.
 3. An actuator structural body according to claim2, wherein said power transmitting means comprises a ball screw shaft.4. An actuator structural body according to claim 2, wherein said powertransmitting means comprises a timing belt.
 5. An actuator structuralbody according to claim 4, wherein said timing belt is driven by a drivepulley integrally formed with said induction motor.
 6. An actuatorstructural body according to claim 2, further comprising a gear fortransmitting rotative forces from the induction motors, and a timingbelt having teeth held in mesh with said gear.
 7. An actuator structuralbody according to claim 4, wherein said timing belt has a longitudinalridge.
 8. An actuator structural body according to claim 2, wherein saiddisplacement detecting means comprises an encoder for detecting angulardisplacement of the motors.
 9. An actuator structural body according toclaim 2, wherein said displacement detecting means comprises a magnetmounted on the movable body and a magnetic sensor mounted on thestructural body.
 10. An actuator structural body according to claim 2,wherein the movable body is slidably disposed on a guide mounted on thestructural body.
 11. An actuator structural body according to claim 1,wherein said joint means is disposed on an end of one of the columnarbodies, and has a T-shaped head fitted in the T-shaped groove defined inthe outer side surface of the other of the columnar bodies.
 12. Anactuator structural body according to claim 1, wherein said joint meanscomprises:an engaging member having a shank inserted in the through holeof said columnar member and a head complementary to the T-shaped groove,said shank having a recess defined therein; and a tightening memberthreaded in a threaded hole which is defined in said columnar member incommunication with said through hole, and having a conical surface on atip end thereof.
 13. An actuator structural body according to claim 1,wherein said joint means comprises:a block having, on a surface thereof,a protrusion inserted in the through hole of said columnar member and atooth inserted in the T-shaped groove of said columnar member, saidblock having a first recess defined in another surface thereof, and athreaded hole defined therein and extending a side surface thereoftoward said first recess; an engaging member having a shank inserted inthe first recess of said block and having a second recess defined in aside surface thereof, and a head complementary to the T-shaped groove;and a tightening member threaded in a threaded hole which is defined insaid columnar member in communication with said through hole, and havinga conical surface on a tip end thereof.
 14. An actuator structural bodyaccording to claim 1, wherein said joint means comprises:an engagingmember having a shank inserted in an end of the through hole of saidcolumnar member and a head complementary to the T-shaped groove, saidengaging member having a first bevel gear on said shank; and atightening member inserted in a hole defined in said columnar member incommunication with said through hole, said tightening member having asecond bevel gear on a tip end thereof which is held in mesh with saidfirst bevel gear.
 15. An actuator structural body according to claim 1,wherein each of said columnar bodies has two parallel grooves defined inone side surface thereof.
 16. An actuator structural body according toclaim 1, wherein the through hole of said columnar member is dividedinto a plurality of through holes.
 17. An actuator structural bodyaccording to claim 1, wherein wires for energizing said actuator aredisposed in the through hole of said columnar member.
 18. An actuatorstructural body according to claim 1, wherein the through hole of saidcolumnar member serves as a fluid passage.
 19. An actuator structuralbody according to claim 1, wherein the through hole of said columnarmember has a coated inner wall surface.
 20. An actuator structural bodyaccording to claim 1, wherein said joint means comprises a reinforcingmember held against an outer surface of each of two structural members,and a bolt inserted through a hole defined in said reinforcing memberinto a T-shaped groove defined in each of the structural members.
 21. Anactuator structural body according to claim 1, wherein said actuatorcomprises:a cylinder for displacing a piston; a fixed pulley disposed onan actuator body at a stroke end of said cylinder; a drive pulleymounted in a pulley body connected to a piston rod of said cylinder; amovable member displaceable by drive forces from said cylinder; and awire trained around said drive pulley and said fixed pulley, said wirehaving an end fixed to a balancer body at the stroke end of saidcylinder and an opposite end fixed to said joint means.
 22. An actuatorstructural body according to claim 1, wherein said actuator comprises:afixed pulley disposed on the actuator body remotely from the stroke endof said cylinder; an adjusting pulley mounted in said pulley body; and awire trained around said drive pulley and said adjusting pulley, saidfrom wire having an end fixed to the balancer body remotely from thestroke end of said cylinder and an opposite end fixed to said movablemember.
 23. An actuator structural body according to claim 21, whereinsaid movable member is integral with a movable body.